Add docstrings to Notifier class

flake8/notifier.py

@@ -3,9 +3,31 @@ from flake8 import _trie
 
 class Notifier(object):
     def __init__(self):
+        """Initialize an empty notifier object."""
         self.listeners = _trie.Trie()
 
     def listeners_for(self, error_code):
+        """Retrieve listeners for an error_code.
+
+        The error code does not need to be a specific error code. For example,
+        There may be listeners registered for E100, E101, E110, E112, and
+        E126. If you wanted to get all listeners starting with 'E1' then you
+        would pass 'E1' as the error code here.
+
+        Example usage
+
+        .. code-block:: python
+
+            from flake8 import notifier
+
+            n = notifier.Notifier()
+            # register listeners
+            for listener in n.listeners_for('E1'):
+                listener.notify(...)
+
+            for listener in n.listeners_for('W102'):
+                listener.notify(...)
+        """
         node = self.listeners.find(error_code)
         if node is None:
             return
@@ -16,8 +38,10 @@ class Notifier(object):
                 yield listener
 
     def notify(self, error_code, *args, **kwargs):
+        """Notify all listeners for the specified error code."""
         for listener in self.listeners_for(error_code):
             listener.notify(*args, **kwargs)
 
     def register_listener(self, error_code, listener):
+        """Register a listener for a specific error_code."""
         self.listeners.add(error_code, listener)