`Entity.columns` class property replaced by `Entity.get_columns` method.

Again, Python < 3.9 doesn't like the combination of `@property` +
`@classmethod`.

platypush/entities/_base.py

@@ -117,9 +117,8 @@ if 'entity' not in Base.metadata:
             'polymorphic_on': type,
         }
 
-        @classmethod  # type: ignore
-        @property
-        def columns(cls) -> Tuple[ColumnProperty, ...]:
+        @classmethod
+        def get_columns(cls) -> Tuple[ColumnProperty, ...]:
             inspector = schema_inspect(cls)
             return tuple(inspector.mapper.column_attrs)
 
@@ -146,7 +145,7 @@ if 'entity' not in Base.metadata:
             return self.__class__(
                 **dict(
                     key_value_pair(col)  # type: ignore
-                    for col in self.columns
+                    for col in self.get_columns()
                     if key_value_pair(col) is not None
                 ),
                 children=[child.copy() for child in self.children],
@@ -213,7 +212,7 @@ if 'entity' not in Base.metadata:
             return {
                 **dict(
                     self._column_to_pair(col)
-                    for col in self.columns
+                    for col in self.get_columns()
                     if self._column_to_pair(col)
                 ),
                 'children_ids': self.children_ids,
@@ -241,7 +240,7 @@ if 'entity' not in Base.metadata:
             """
             Serializes the new value before assigning it to an attribute.
             """
-            matching_columns = [c for c in self.columns if c.expression.name == key]  # type: ignore
+            matching_columns = [c for c in self.get_columns() if c.expression.name == key]  # type: ignore
 
             if (
                 matching_columns

platypush/entities/_engine/repo/merger.py

@@ -176,7 +176,7 @@ class EntitiesMerger:
         """
         Merge two versions of an entity column by column.
         """
-        columns = [col.key for col in entity.columns]
+        columns = [col.key for col in entity.get_columns()]
         for col in columns:
             if col == 'meta':
                 existing_entity.meta = {  # type: ignore
@@ -189,7 +189,9 @@ class EntitiesMerger:
                 except ObjectDeletedError as e:
                     logger.warning(
                         'Could not set %s on entity <%s>: %s',
-                        col, existing_entity.entity_key, e
+                        col,
+                        existing_entity.entity_key,
+                        e,
                     )
 
         # Recursive call to merge the columns of the children too

platypush/plugins/rss/__init__.py

@@ -44,6 +44,8 @@ class RssPlugin(RunnablePlugin):
         + 'Chrome/62.0.3202.94 Safari/537.36'
     )
 
+    timeout = 20
+
     def __init__(
         self,
         subscriptions: Optional[Collection[str]] = None,
@@ -117,7 +119,9 @@ class RssPlugin(RunnablePlugin):
         import feedparser
 
         feed = feedparser.parse(
-            requests.get(url, headers={'User-Agent': self.user_agent}, timeout=20).text,
+            requests.get(
+                url, headers={'User-Agent': self.user_agent}, timeout=self.timeout
+            ).text,
         )
         return RssFeedEntrySchema().dump(
             sorted(
@@ -200,6 +204,7 @@ class RssPlugin(RunnablePlugin):
                     headers={
                         'User-Agent': self.user_agent,
                     },
+                    timeout=self.timeout,
                 ).text
             except Exception as e:
                 self.logger.warning('Could not retrieve subscription %s: %s', url, e)
@@ -365,7 +370,7 @@ class RssPlugin(RunnablePlugin):
                 url = response['url']
                 error = response.get('error')
                 if error:
-                    self.logger.error(f'Could not parse feed {url}: {error}')
+                    self.logger.error('Could not parse feed %s: %s', url, error)
                     responses[url] = error
                 else:
                     responses[url] = response['content']