Improved docs and typing

classes/callbacks.py

@@ -9,7 +9,20 @@ class CallbackLanguage:
 
     @classmethod
     def from_callback(cls, callback: CallbackQuery):
+        """Parse callback query and extract language data from it.
+
+        ### Args:
+            * callback (`CallbackQuery`): Callback query got from user interaction.
+
+        ### Raises:
+            * `ValueError`: Raised when callback provided is not a language one.
+
+        ### Returns:
+            * `CallbackLanguage`: Parsed callback query.
+        """
         action, language = str(callback.data).split(":")
+
         if action.lower() != "language":
             raise ValueError("Callback provided is not a language callback")
+
         return cls(language)