added utils aggregate to simplify code design

app/utils/utils.py

@@ -0,0 +1,44 @@
+import logging
+
+from aiohttp import ClientSession
+from dateutil.parser import parse
+
+class Utils: 
+    # Singleton aiohttp.ClientSession instance.
+    CLIENT_SESSION: ClientSession
+
+    LOGGER = logging.getLogger(__name__)
+
+    async def setup_client_session():
+        """Set up the application-global aiohttp.ClientSession instance.
+
+        aiohttp recommends that only one ClientSession exist for the lifetime of an application.
+        See: https://docs.aiohttp.org/en/stable/client_quickstart.html#make-a-request
+
+        """
+        global CLIENT_SESSION  # pylint: disable=global-statement
+        LOGGER.info("Setting up global aiohttp.ClientSession.")
+        CLIENT_SESSION = ClientSession()
+
+    async def teardown_client_session():
+        """Close the application-global aiohttp.ClientSession.
+        """
+        global CLIENT_SESSION  # pylint: disable=global-statement
+        LOGGER.info("Closing global aiohttp.ClientSession.")
+        await CLIENT_SESSION.close()
+
+
+    def is_date(string, fuzzy=False):
+        """
+        Return whether the string can be interpreted as a date.
+        - https://stackoverflow.com/a/25341965/7120095
+
+        :param string: str, string to check for date
+        :param fuzzy: bool, ignore unknown tokens in string if True
+        """
+
+        try:
+            parse(string, fuzzy=fuzzy)
+            return True
+        except ValueError:
+            return False