extensive docstrings; made all functions public (not protected); minor refactoring

src/mwfin/__main__.py

@@ -19,6 +19,7 @@ VERBOSE = 'verbose'
 
 
 def parse_cli() -> dict:
+    """Returns the parsed command line arguments for the program as a dictionary."""
     parser = ArgumentParser(description="Scrape company financials")
     parser.add_argument(
         TICKER_SYMBOL,
@@ -36,7 +37,7 @@ def parse_cli() -> dict:
         type=int,
         default=DEFAULT_CONCURRENT_BATCH_SIZE,
         help="If multiple ticker symbols are passed, the company financials can be scraped concurrently. "
-             "This argument determines how many companies are scraped concurrently at any moment in time. "
+             "This argument determines how many companies are scraped concurrently. "
              "By default, they are scraped sequentially (i.e. a batch size of 1)."
     )
     parser.add_argument(
@@ -61,6 +62,10 @@ def parse_cli() -> dict:
 
 
 def configure_logging(verbosity: int) -> None:
+    """
+    Sets up logging by adding a stdout-handler and setting the root logger's level according to the specified verbosity.
+    A verbosity of 0 (or less) sets the log level to CRITICAL.
+    """
     root_logger = logging.getLogger()
     root_logger.addHandler(logging.StreamHandler())
     root_logger.setLevel(logging.CRITICAL)
@@ -73,6 +78,7 @@ def configure_logging(verbosity: int) -> None:
 
 
 async def main() -> None:
+    """Parses CLI arguments, configures logging to stderr, performs the scraping, and prints/saves the data."""
     args = parse_cli()
     configure_logging(args[VERBOSE])
     data = await get_all_financials(*args[TICKER_SYMBOL], quarterly=args[QUARTERLY],

src/mwfin/functions.py

@@ -1,10 +1,10 @@
 import logging
 import asyncio
-from typing import Union, Tuple, List, Dict
+from typing import Union, Tuple, Dict
 
 from aiohttp.client import ClientSession
 from bs4 import BeautifulSoup
-from bs4.element import Tag
+from bs4.element import Tag, ResultSet
 from webutils import in_async_session, gather_in_batches
 
 from .constants import (HTML_PARSER, BASE_URL, END_DATE, BS, IS, CF, FIN_STMT_URL_SUFFIX, DEFAULT_CONCURRENT_BATCH_SIZE,
@@ -13,12 +13,12 @@ from .constants import (HTML_PARSER, BASE_URL, END_DATE, BS, IS, CF, FIN_STMT_UR
 
 log = logging.getLogger(__name__)
 
-# The resulting dictionary's keys correspond to the name of the item (row) in the financial statement,
+# First element in each Tuple is an integer indicating the row indent
-# while its values will always be tuples with a length corresponding to the number of periods (columns)
-# and elements being the actual numbers, with the exception of the first key-value-pair, which will represent
-# the end dates of the reporting periods as strings (either years or quarters).
 HeaderData = Tuple[int, str, str, str, str, str]
 RowData = Tuple[int, float, float, float, float, float]
+# The resulting dictionary's keys correspond to the name of the item (row) in the financial statement.
+# The first value is a tuple of the end dates of the reporting periods as strings (see above).
+# The other values are the actual data tuples containing the financial figures.
 ResultDict = dict[str, Union[HeaderData, RowData]]
 
 
@@ -26,6 +26,16 @@ ResultDict = dict[str, Union[HeaderData, RowData]]
 async def soup_from_url(url: str, session: ClientSession = None) -> BeautifulSoup:
     """
     Requests a web page and turns the response text into BeautifulSoup.
+
+    Args:
+        url:
+            The GET request is sent to this URL
+        session (optional):
+            If passed an `aiohttp.ClientSession` object, it will be used to perform the request.
+            Otherwise a new session is created and automatically closed after the request (see `@in_async_session`).
+
+    Returns:
+        The parsed html response text as BeautifulSoup
     """
     async with session.get(url) as response:
         html = await response.text()
@@ -33,6 +43,17 @@ async def soup_from_url(url: str, session: ClientSession = None) -> BeautifulSou
 
 
 def get_row_indent(tr: Tag) -> int:
+    """
+    Determines the visual indent of a table row.
+    Some positions in a financial statement have sub-positions below them indicated by indentation of the text in the
+    position name's cell.
+
+    Args:
+        tr: The table row element
+
+    Returns:
+        Each indentation level corresponds to an integer. 0 = no indentation, 1 = small, 2 = medium, 3 = large
+    """
     try:
         classes = tr.div.attrs['class']
     except KeyError:
@@ -47,15 +68,27 @@ def extract_end_dates(soup: BeautifulSoup) -> HeaderData:
     """
     Finds and returns the end dates of the reporting periods as strings (either years or quarters) from the page of a
     financial statement.
+
+    Args:
+        soup: The parsed page containing the financial statement
+
+    Returns:
+        A 6-tuple, the first element being the indent (in this case 0) and the rest being the actual end dates.
     """
     tr = soup.find('div', attrs={'class': 'financials'}).thead.tr
     ths = tr.find_all('th')
-    return (get_row_indent(tr), ) + tuple(str(th.string).strip() for th in ths[1:-1])
+    return (0, ) + tuple(str(th.string).strip() for th in ths[1:-1])
 
 
-def get_all_table_rows(soup: BeautifulSoup) -> List[Tag]:
+def get_all_table_rows(soup: BeautifulSoup) -> ResultSet:
     """
     Returns the table rows containing the data of interest.
+
+    Args:
+        soup: The parsed page containing the financial statement
+
+    Returns:
+        All table rows containing data from the financial statement
     """
     return soup.find('div', attrs={'class': 'financials'}).tbody.find_all('tr')
 
@@ -63,7 +96,14 @@ def get_all_table_rows(soup: BeautifulSoup) -> List[Tag]:
 def extract_row_data(tr: Tag) -> Tuple[str, RowData]:
     """
     Returns the name of the item displayed in the table row (of a financial statement)
-    as well as a number for each reporting period.
+    as well as the position's indent and a figure for each reporting period.
+
+    Args:
+        tr: A table row containing data from a financial statement
+
+    Returns:
+        2-tuple where the 1st element is the position's name and the second is a 6-tuple, of which the first element is
+        the indent and the rest are the actual figures.
     """
     item_name = str(tr.td.div.string).strip()
     data_div = tr.find_all('td')[-1].div.div
@@ -74,7 +114,14 @@ def extract_row_data(tr: Tag) -> Tuple[str, RowData]:
 
 def extract_all_data(soup: BeautifulSoup) -> ResultDict:
     """
-    Extracts financials from the page.
+    Extracts financials from the page, which can contain either a balance sheet, income statement or cash flow
+    statement.
+
+    Args:
+        soup: The parsed page containing a financial statement
+
+    Returns:
+        Custom result dictionary (see `ResultDict`)
     """
     output = {END_DATE: extract_end_dates(soup)}
     for row in get_all_table_rows(soup):
@@ -84,10 +131,23 @@ def extract_all_data(soup: BeautifulSoup) -> ResultDict:
 
 
 @in_async_session
-async def _get_single_company_fin_stmt(statement: str, ticker_symbol: str, quarterly: bool = False,
+async def get_single_company_fin_stmt(statement: str, ticker_symbol: str, quarterly: bool = False,
-                                       session: ClientSession = None) -> ResultDict:
+                                      session: ClientSession = None) -> ResultDict:
     """
     Returns data from the specified financial statement of the specified company.
+
+    Args:
+        statement:
+            Must be one of the strings defined in the constants `BS`, `IS`, `CF`
+        ticker_symbol:
+            The company's stock ticker symbol
+        quarterly (optional):
+            If true the financial data of the last five quarters is scraped; otherwise (default) the last five years.
+        session (optional):
+            See `soup_from_url`
+
+    Returns:
+        Custom result dictionary (see `ResultDict`)
     """
     log.info(f"Scraping {statement} for {ticker_symbol}")
     url = f'{BASE_URL}/{ticker_symbol}/financials{FIN_STMT_URL_SUFFIX[statement]}'
@@ -98,12 +158,34 @@ async def _get_single_company_fin_stmt(statement: str, ticker_symbol: str, quart
 
 
 @in_async_session
-async def _get_multi_companies_fin_stmt(statement: str, *ticker_symbols: str, quarterly: bool = False,
+async def get_multi_companies_fin_stmt(statement: str, *ticker_symbols: str, quarterly: bool = False,
-                                        concurrent_batch_size: int = DEFAULT_CONCURRENT_BATCH_SIZE,
+                                       concurrent_batch_size: int = DEFAULT_CONCURRENT_BATCH_SIZE,
-                                        session: ClientSession = None) -> Union[ResultDict, Dict[str, ResultDict]]:
+                                       session: ClientSession = None) -> Union[ResultDict, Dict[str, ResultDict]]:
+    """
+    Returns data from the specified financial statement of the specified companies.
+
+    Args:
+        statement:
+            See `get_single_company_fin_stmt`
+        ticker_symbols:
+            Arbitrary number of companies' stock ticker symbols
+        quarterly (optional):
+            See `get_single_company_fin_stmt`
+        concurrent_batch_size (optional):
+            If multiple ticker symbols are passed, the company financials can be scraped concurrently.
+            This argument determines how many companies are scraped concurrently.
+            By default, they are scraped sequentially (i.e. a batch size of 1).
+        session (optional):
+            See `get_single_company_fin_stmt`
+
+    Returns:
+        If only one ticker symbol is passed, the `ResultDict` for that financial statement is returned. If multiple
+        symbols are passed, a dictionary is returned, where the keys are the symbols and the values are the
+        corresponding `ResultDict`s.
+    """
     if len(ticker_symbols) == 1:
-        return await _get_single_company_fin_stmt(statement, ticker_symbols[0], quarterly, session)
+        return await get_single_company_fin_stmt(statement, ticker_symbols[0], quarterly, session)
-    coroutines = (_get_single_company_fin_stmt(statement, symbol, quarterly, session) for symbol in ticker_symbols)
+    coroutines = (get_single_company_fin_stmt(statement, symbol, quarterly, session) for symbol in ticker_symbols)
     result_list = await gather_in_batches(concurrent_batch_size, *coroutines)
     return {symbol: data for symbol, data in zip(ticker_symbols, result_list)}
 
@@ -113,11 +195,12 @@ async def get_balance_sheet(*ticker_symbols: str, quarterly: bool = False,
                             concurrent_batch_size: int = DEFAULT_CONCURRENT_BATCH_SIZE,
                             session: ClientSession = None) -> Union[ResultDict, Dict[str, ResultDict]]:
     """
-    Returns data from the balance sheet of the specified company.
+    Returns data from the balance sheet of the specified companies.
+    Convenience function around `get_multi_companies_fin_stmt`
     """
-    return await _get_multi_companies_fin_stmt(BS, *ticker_symbols,
+    return await get_multi_companies_fin_stmt(BS, *ticker_symbols,
-                                               quarterly=quarterly, concurrent_batch_size=concurrent_batch_size,
+                                              quarterly=quarterly, concurrent_batch_size=concurrent_batch_size,
-                                               session=session)
+                                              session=session)
 
 
 @in_async_session
@@ -125,11 +208,12 @@ async def get_income_statement(*ticker_symbols: str, quarterly: bool = False,
                                concurrent_batch_size: int = DEFAULT_CONCURRENT_BATCH_SIZE,
                                session: ClientSession = None) -> Union[ResultDict, Dict[str, ResultDict]]:
     """
-    Returns data from the income statement of the specified company.
+    Returns data from the income statement of the specified companies.
+    Convenience function around `get_multi_companies_fin_stmt`
     """
-    return await _get_multi_companies_fin_stmt(IS, *ticker_symbols,
+    return await get_multi_companies_fin_stmt(IS, *ticker_symbols,
-                                               quarterly=quarterly, concurrent_batch_size=concurrent_batch_size,
+                                              quarterly=quarterly, concurrent_batch_size=concurrent_batch_size,
-                                               session=session)
+                                              session=session)
 
 
 @in_async_session
@@ -137,17 +221,34 @@ async def get_cash_flow_statement(*ticker_symbols: str, quarterly: bool = False,
                                   concurrent_batch_size: int = DEFAULT_CONCURRENT_BATCH_SIZE,
                                   session: ClientSession = None) -> Union[ResultDict, Dict[str, ResultDict]]:
     """
-    Returns data from the cash flow statement of the specified company.
+    Returns data from the cash flow statement of the specified companies.
+    Convenience function around `get_multi_companies_fin_stmt`
     """
-    return await _get_multi_companies_fin_stmt(CF, *ticker_symbols,
+    return await get_multi_companies_fin_stmt(CF, *ticker_symbols,
-                                               quarterly=quarterly, concurrent_batch_size=concurrent_batch_size,
+                                              quarterly=quarterly, concurrent_batch_size=concurrent_batch_size,
-                                               session=session)
+                                              session=session)
 
 
 @in_async_session
-async def _get_single_company_all_financials(ticker_symbol: str, quarterly: bool = False,
+async def get_single_company_all_financials(ticker_symbol: str, quarterly: bool = False,
-                                             session: ClientSession = None) -> Dict[str, ResultDict]:
+                                            session: ClientSession = None) -> Dict[str, ResultDict]:
-    coroutines = (_get_single_company_fin_stmt(stmt, ticker_symbol, quarterly, session) for stmt in (BS, IS, CF))
+    """
+    Returns data from all financial statements of the specified company.
+    Concurrently calls `get_single_company_fin_stmt` three times.
+
+    Args:
+        ticker_symbol:
+            The company's stock ticker symbol
+        quarterly (optional):
+            See `get_single_company_fin_stmt`
+        session (optional):
+            See `get_single_company_fin_stmt`
+
+    Returns:
+        A dictionary where the keys are the three different statement names and the values are the
+        corresponding `ResultDict`s
+    """
+    coroutines = (get_single_company_fin_stmt(stmt, ticker_symbol, quarterly, session) for stmt in (BS, IS, CF))
     results = await asyncio.gather(*coroutines)
     return {stmt: data for stmt, data in zip((BS, IS, CF), results)}
 
@@ -158,10 +259,27 @@ async def get_all_financials(*ticker_symbols: str, quarterly: bool = False,
                              session: ClientSession = None) -> Union[Dict[str, ResultDict],
                                                                      Dict[str, Dict[str, ResultDict]]]:
     """
-    Returns all fundamentals (balance sheet, income statement and cash flow statement) of the specified company.
+    Returns all fundamentals (balance sheet, income statement and cash flow statement) of the specified companies.
+
+    Args:
+        ticker_symbols:
+            Arbitrary number of companies' stock ticker symbols
+        quarterly (optional):
+            See `get_single_company_all_financials`
+        concurrent_batch_size (optional):
+            If multiple ticker symbols are passed, the company financials can be scraped concurrently.
+            This argument determines how many companies are scraped concurrently.
+            By default, they are scraped sequentially (i.e. a batch size of 1).
+        session (optional):
+            See `get_single_company_all_financials`
+
+    Returns:
+        If only one ticker symbol is passed, the output of `get_single_company_all_financials` is returned. If multiple
+        symbols are passed, a dictionary is returned, where the keys are the symbols and the values are the
+        corresponding outputs of `get_single_company_all_financials`.
     """
     if len(ticker_symbols) == 1:
-        return await _get_single_company_all_financials(ticker_symbols[0], quarterly, session)
+        return await get_single_company_all_financials(ticker_symbols[0], quarterly, session)
-    coroutines = (_get_single_company_all_financials(symbol, quarterly, session) for symbol in ticker_symbols)
+    coroutines = (get_single_company_all_financials(symbol, quarterly, session) for symbol in ticker_symbols)
     result_list = await gather_in_batches(concurrent_batch_size, *coroutines)
     return {symbol: data for symbol, data in zip(ticker_symbols, result_list)}

tests/test_functions.py

@@ -108,7 +108,7 @@ class FunctionsTestCase(IsolatedAsyncioTestCase):
 
     @patch.object(functions, 'extract_all_data')
     @patch.object(functions, 'soup_from_url')
-    async def test__get_single_company_fin_stmt(self, mock_soup_from_url, mock_extract_all_data):
+    async def test_get_single_company_fin_stmt(self, mock_soup_from_url, mock_extract_all_data):
         mock_session = MagicMock()
         test_ticker, statement = 'bar', BS
         test_url = f'{BASE_URL}/{test_ticker}/financials{FIN_STMT_URL_SUFFIX[statement]}'
@@ -116,7 +116,7 @@ class FunctionsTestCase(IsolatedAsyncioTestCase):
         mock_extract_all_data.return_value = expected_output = {'foo': 'bar'}
 
         quarterly = False
-        output = await functions._get_single_company_fin_stmt(statement, test_ticker, quarterly, mock_session)
+        output = await functions.get_single_company_fin_stmt(statement, test_ticker, quarterly, mock_session)
         self.assertDictEqual(expected_output, output)
         mock_soup_from_url.assert_called_once_with(test_url, mock_session)
         mock_extract_all_data.assert_called_once_with(mock_soup)
@@ -124,33 +124,33 @@ class FunctionsTestCase(IsolatedAsyncioTestCase):
         mock_extract_all_data.reset_mock()
 
         quarterly = True
-        output = await functions._get_single_company_fin_stmt(statement, test_ticker, quarterly, mock_session)
+        output = await functions.get_single_company_fin_stmt(statement, test_ticker, quarterly, mock_session)
         self.assertDictEqual(expected_output, output)
         mock_soup_from_url.assert_called_once_with(test_url + '/quarter', mock_session)
         mock_extract_all_data.assert_called_once_with(mock_soup)
 
-    @patch.object(functions, '_get_single_company_fin_stmt')
+    @patch.object(functions, 'get_single_company_fin_stmt')
-    async def test__get_multi_companies_fin_stmt(self, mock__get_single_company_fin_stmt):
+    async def test_get_multi_companies_fin_stmt(self, mock_get_single_company_fin_stmt):
         statement, sym1, sym2, quarterly, mock_session = 'xyz', 'foo', 'bar', False, MagicMock()
-        mock__get_single_company_fin_stmt.return_value = expected_output = 'baz'
+        mock_get_single_company_fin_stmt.return_value = expected_output = 'baz'
-        output = await functions._get_multi_companies_fin_stmt(statement, sym1,
+        output = await functions.get_multi_companies_fin_stmt(statement, sym1,
-                                                               quarterly=quarterly, session=mock_session)
+                                                              quarterly=quarterly, session=mock_session)
         self.assertEqual(expected_output, output)
-        mock__get_single_company_fin_stmt.assert_called_once_with(statement, sym1, quarterly, mock_session)
+        mock_get_single_company_fin_stmt.assert_called_once_with(statement, sym1, quarterly, mock_session)
-        mock__get_single_company_fin_stmt.reset_mock()
+        mock_get_single_company_fin_stmt.reset_mock()
 
         expected_output = {sym1: expected_output, sym2: expected_output}
-        output = await functions._get_multi_companies_fin_stmt(statement, sym1, sym2,
+        output = await functions.get_multi_companies_fin_stmt(statement, sym1, sym2,
-                                                               quarterly=quarterly, session=mock_session)
+                                                              quarterly=quarterly, session=mock_session)
         self.assertDictEqual(expected_output, output)
-        mock__get_single_company_fin_stmt.assert_has_calls([
+        mock_get_single_company_fin_stmt.assert_has_calls([
             call(statement, sym1, quarterly, mock_session),
             call(statement, sym2, quarterly, mock_session)
         ])
 
-    async def _helper_test_get_any_statement(self, stmt: str, mock__get_multi_companies_fin_stmt):
+    async def _helper_test_get_any_statement(self, stmt: str, mock_get_multi_companies_fin_stmt):
         sym1, sym2, quarterly, batch_size, mock_session = 'foo', 'bar', False, 2, MagicMock()
-        mock__get_multi_companies_fin_stmt.return_value = expected_output = 'baz'
+        mock_get_multi_companies_fin_stmt.return_value = expected_output = 'baz'
         if stmt == BS:
             function = functions.get_balance_sheet
         elif stmt == IS:
@@ -161,50 +161,50 @@ class FunctionsTestCase(IsolatedAsyncioTestCase):
             raise ValueError
         output = await function(sym1, sym2, quarterly=quarterly, concurrent_batch_size=batch_size, session=mock_session)
         self.assertEqual(expected_output, output)
-        mock__get_multi_companies_fin_stmt.assert_called_once_with(
+        mock_get_multi_companies_fin_stmt.assert_called_once_with(
             stmt, sym1, sym2, quarterly=quarterly, concurrent_batch_size=batch_size, session=mock_session
         )
 
-    @patch.object(functions, '_get_multi_companies_fin_stmt')
+    @patch.object(functions, 'get_multi_companies_fin_stmt')
-    async def test_get_balance_sheet(self, mock__get_multi_companies_fin_stmt):
+    async def test_get_balance_sheet(self, mock_get_multi_companies_fin_stmt):
-        await self._helper_test_get_any_statement(BS, mock__get_multi_companies_fin_stmt)
+        await self._helper_test_get_any_statement(BS, mock_get_multi_companies_fin_stmt)
 
-    @patch.object(functions, '_get_multi_companies_fin_stmt')
+    @patch.object(functions, 'get_multi_companies_fin_stmt')
-    async def test_get_income_statement(self, mock__get_multi_companies_fin_stmt):
+    async def test_get_income_statement(self, mock_get_multi_companies_fin_stmt):
-        await self._helper_test_get_any_statement(IS, mock__get_multi_companies_fin_stmt)
+        await self._helper_test_get_any_statement(IS, mock_get_multi_companies_fin_stmt)
 
-    @patch.object(functions, '_get_multi_companies_fin_stmt')
+    @patch.object(functions, 'get_multi_companies_fin_stmt')
-    async def test_get_cash_flow_statement(self, mock__get_multi_companies_fin_stmt):
+    async def test_get_cash_flow_statement(self, mock_get_multi_companies_fin_stmt):
-        await self._helper_test_get_any_statement(CF, mock__get_multi_companies_fin_stmt)
+        await self._helper_test_get_any_statement(CF, mock_get_multi_companies_fin_stmt)
 
-    @patch.object(functions, '_get_single_company_fin_stmt')
+    @patch.object(functions, 'get_single_company_fin_stmt')
-    async def test__get_single_company_all_financials(self, mock__get_single_company_fin_stmt):
+    async def test_get_single_company_all_financials(self, mock_get_single_company_fin_stmt):
         symbol, quarterly, mock_session = 'foo', False, MagicMock()
-        mock__get_single_company_fin_stmt.return_value = bar = 'bar'
+        mock_get_single_company_fin_stmt.return_value = bar = 'bar'
         expected_output = {BS: bar, IS: bar, CF: bar}
-        output = await functions._get_single_company_all_financials(symbol, quarterly, mock_session)
+        output = await functions.get_single_company_all_financials(symbol, quarterly, mock_session)
         self.assertDictEqual(expected_output, output)
-        mock__get_single_company_fin_stmt.assert_has_calls([
+        mock_get_single_company_fin_stmt.assert_has_calls([
             call(BS, symbol, quarterly, mock_session),
             call(IS, symbol, quarterly, mock_session),
             call(CF, symbol, quarterly, mock_session)
         ])
 
-    @patch.object(functions, '_get_single_company_all_financials')
+    @patch.object(functions, 'get_single_company_all_financials')
-    async def test_get_company_financials(self, mock__get_single_company_all_financials):
+    async def test_get_company_financials(self, mock_get_single_company_all_financials):
-        mock__get_single_company_all_financials.return_value = expected_output = 'baz'
+        mock_get_single_company_all_financials.return_value = expected_output = 'baz'
         symbol, quarterly, mock_session = 'foo', False, MagicMock()
         output = await functions.get_all_financials(symbol, quarterly=quarterly, session=mock_session)
         self.assertEqual(expected_output, output)
-        mock__get_single_company_all_financials.assert_called_once_with(symbol, quarterly, mock_session)
+        mock_get_single_company_all_financials.assert_called_once_with(symbol, quarterly, mock_session)
-        mock__get_single_company_all_financials.reset_mock()
+        mock_get_single_company_all_financials.reset_mock()
 
         test_sym1, test_sym2 = 'x', 'y'
         expected_output = {test_sym1: expected_output, test_sym2: expected_output}
         output = await functions.get_all_financials(test_sym1, test_sym2,
                                                     quarterly=quarterly, session=mock_session)
         self.assertDictEqual(expected_output, output)
-        mock__get_single_company_all_financials.assert_has_calls([
+        mock_get_single_company_all_financials.assert_has_calls([
             call(test_sym1, quarterly, mock_session),
             call(test_sym2, quarterly, mock_session)
         ])