TV grabber ttvdb.py fails with newer versions of

python package request-cache.

This was reported on the forum, it throws this
Error: (module 'requests_cache' has no attribute 'core')

It turned out, that the monkey patch provided by
`mythtv/bindings/python/MythTV/ttvdb/requests_cache_compatability.py`
is only valid for versions of request-cache < '0.5.0'. Newer versions
do not need this patch and versions beyond '0.8.0' crashes with above
error message.
Note: The module requests_cache.core was removed in version '0.8.0'
on Sept. 2021 and deprecated in version '0.6.0' in April, 2021.

Refs #408

(cherry picked from commit da3f006)

mythtv/bindings/python/MythTV/ttvdb/requests_cache_compatability.py

@@ -12,38 +12,41 @@
 import requests_cache
 from datetime import datetime, timedelta
 
-# patch if required if older versions of
-try:
-    requests_cache.backends.base.BaseCache.remove_old_entries
-except Exception as e:
-    def remove_old_entries(self, created_before):
-        """ Deletes entries from cache with creation time older than ``created_before``
-        """
-        keys_to_delete = set()
-        for key in self.responses:
-            try:
-                response, created_at = self.responses[key]
-            except KeyError:
-                continue
-            if created_at < created_before:
-                keys_to_delete.add(key)
-
-        for key in keys_to_delete:
-            self.delete(key)
-
-
-    def remove_expired_responses(self):
-        """ Removes expired responses from storage
-        """
-        if not self._cache_expire_after:
-            return
-        # just in case expire_after is not converted in the
-        #  original constructor, convert it to a timedelta
-        if not isinstance(self._cache_expire_after, timedelta):
-            self._cache_expire_after = timedelta(seconds=self._cache_expire_after)
-
-        self.cache.remove_old_entries(datetime.utcnow() - self._cache_expire_after)
-
-
-    requests_cache.backends.base.BaseCache.remove_old_entries = remove_old_entries
-    requests_cache.core.CachedSession.remove_expired_responses = remove_expired_responses
+rc_version_info = tuple(int(x) for x in requests_cache.__version__.split('.'))
+# patch if required if older versions than '0.5.0'
+# request_cache.core is deprecated in '0.6.0' and removed on '0.8.0'.
+if rc_version_info < (0, 5, 0):
+    try:
+        requests_cache.backends.base.BaseCache.remove_old_entries
+    except Exception as e:
+        def remove_old_entries(self, created_before):
+            """ Deletes entries from cache with creation time older than ``created_before``
+            """
+            keys_to_delete = set()
+            for key in self.responses:
+                try:
+                    response, created_at = self.responses[key]
+                except KeyError:
+                    continue
+                if created_at < created_before:
+                    keys_to_delete.add(key)
+
+            for key in keys_to_delete:
+                self.delete(key)
+
+
+        def remove_expired_responses(self):
+            """ Removes expired responses from storage
+            """
+            if not self._cache_expire_after:
+                return
+            # just in case expire_after is not converted in the
+            #  original constructor, convert it to a timedelta
+            if not isinstance(self._cache_expire_after, timedelta):
+                self._cache_expire_after = timedelta(seconds=self._cache_expire_after)
+
+            self.cache.remove_old_entries(datetime.utcnow() - self._cache_expire_after)
+
+
+        requests_cache.backends.base.BaseCache.remove_old_entries = remove_old_entries
+        requests_cache.core.CachedSession.remove_expired_responses = remove_expired_responses