Implement keys() method in av.dictionary.Dictionary to allow calling dict() on it

Author: laggykiller

av/dictionary.py

@@ -42,6 +42,9 @@ def __iter__(self):
     def __repr__(self):
         return f"av.Dictionary({dict(self)!r})"
 
+    def keys(self):
+        return list(self)
+
     def copy(self):
         other: Dictionary = Dictionary()
         lib.av_dict_copy(cython.address(other.ptr), self.ptr, 0)

av/dictionary.pyi

@@ -7,6 +7,7 @@ class Dictionary:
     def __len__(self) -> int: ...
     def __iter__(self) -> Iterator[str]: ...
     def __repr__(self) -> str: ...
+    def keys(self) -> Iterable[str]: ...
     def copy(self) -> Dictionary: ...
     def pop(self, key: str) -> str: ...
     def update(