(#1164) Add types to listing/mixins/subreddit.py (#1209)

praw/models/listing/mixins/subreddit.py

@@ -1,4 +1,5 @@
 """Provide the SubredditListingMixin class."""
+from typing import Any, Dict, Generator, TypeVar, Union
 from urllib.parse import urljoin
 
 from ....util.cache import cachedproperty
@@ -9,33 +10,9 @@
 from .rising import RisingListingMixin
 
 
-class SubredditListingMixin(
-    BaseListingMixin, GildedListingMixin, RisingListingMixin
-):
-    """Adds additional methods pertaining to Subreddit-like instances."""
-
-    @cachedproperty
-    def comments(self):
-        """Provide an instance of :class:`.CommentHelper`.
-
-        For example, to output the author of the 25 most recent comments of
-        ``/r/redditdev`` execute:
-
-        .. code:: python
-
-           for comment in reddit.subreddit('redditdev').comments(limit=25):
-               print(comment.author)
-
-        """
-        return CommentHelper(self)
-
-    def __init__(self, reddit, _data):
-        """Initialize a SubredditListingMixin instance.
-
-        :param reddit: An instance of :class:`.Reddit`.
-
-        """
-        super().__init__(reddit, _data=_data)
+Comment = TypeVar("Comment")
+Reddit = TypeVar("Reddit")
+Subreddit = TypeVar("Subreddit")
 
 
 class CommentHelper(PRAWBase):
@@ -45,12 +22,14 @@ class CommentHelper(PRAWBase):
     def _path(self):
         return urljoin(self.subreddit._path, "comments/")
 
-    def __init__(self, subreddit):
+    def __init__(self, subreddit: Subreddit):
         """Initialize a CommentHelper instance."""
         super().__init__(subreddit._reddit, _data=None)
         self.subreddit = subreddit
 
-    def __call__(self, **generator_kwargs):
+    def __call__(
+        self, **generator_kwargs: Union[str, int, Dict[str, str]]
+    ) -> Generator[Any, None, None]:
         """Return a :class:`.ListingGenerator` for the Subreddit's comments.
 
         Additional keyword arguments are passed in the initialization of
@@ -65,3 +44,32 @@ def __call__(self, **generator_kwargs):
 
         """
         return ListingGenerator(self._reddit, self._path, **generator_kwargs)
+
+
+class SubredditListingMixin(
+    BaseListingMixin, GildedListingMixin, RisingListingMixin
+):
+    """Adds additional methods pertaining to Subreddit-like instances."""
+
+    @cachedproperty
+    def comments(self) -> CommentHelper:
+        """Provide an instance of :class:`.CommentHelper`.
+
+        For example, to output the author of the 25 most recent comments of
+        ``/r/redditdev`` execute:
+
+        .. code:: python
+
+           for comment in reddit.subreddit('redditdev').comments(limit=25):
+               print(comment.author)
+
+        """
+        return CommentHelper(self)
+
+    def __init__(self, reddit: Reddit, _data: Dict[str, Any]):
+        """Initialize a SubredditListingMixin instance.
+
+        :param reddit: An instance of :class:`.Reddit`.
+
+        """
+        super().__init__(reddit, _data=_data)