make media iterable.

they will yield the next lower level. so a show will iter a season a
season will yield a episode etc.

plexapi/audio.py

@@ -78,6 +78,10 @@ class Artist(Audio):
         self.similar = self.findItems(data, media.Similar)
         self.collections = self.findItems(data, media.Collection)
 
+    def __iter__(self):
+        for album in self.albums():
+            yield album
+
     def album(self, title):
         """ Returns the :class:`~plexapi.audio.Album` that matches the specified title.
 
@@ -151,6 +155,10 @@ class Album(Audio):
     TAG = 'Directory'
     TYPE = 'album'
 
+    def __iter__(self):
+        for track in self.tracks:
+            yield track
+
     def _loadData(self, data):
         """ Load attribute values from Plex XML response. """
         Audio._loadData(self, data)

plexapi/base.py

@@ -272,6 +272,9 @@ class PlexPartialObject(PlexObject):
     def __hash__(self):
         return hash(repr(self))
 
+    def __iter__(self):
+        yield self
+
     def __getattribute__(self, attr):
         # Dragons inside.. :-/
         value = utils.getattributeOrNone(PlexPartialObject, self, attr)

plexapi/video.py

@@ -24,6 +24,7 @@ class Video(PlexPartialObject):
             updatedAt (datatime): Datetime this item was updated.
             viewCount (int): Count of times this item was accessed.
     """
+
     def _loadData(self, data):
         """ Load attribute values from Plex XML response. """
         self._data = data
@@ -214,6 +215,10 @@ class Show(Video):
     TAG = 'Directory'
     TYPE = 'show'
 
+    def __iter__(self):
+        for season in self.seasons():
+            yield season
+
     def _loadData(self, data):
         """ Load attribute values from Plex XML response. """
         Video._loadData(self, data)
@@ -335,6 +340,10 @@ class Season(Video):
     TAG = 'Directory'
     TYPE = 'season'
 
+    def __iter__(self):
+        for episode in self.episodes():
+            yield episode
+
     def _loadData(self, data):
         """ Load attribute values from Plex XML response. """
         Video._loadData(self, data)