<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_media_metadata(self, item_id):
 """Get metadata for a media item. Args: item_id (str):
 The item for which metadata is required. Returns: ~collections.OrderedDict: The item's metadata, or `None` See also: The Sonos `getMediaMetadata API <http://musicpartners.sonos.com/node/83>`_ """

        response = self.soap_client.call(
            'getMediaMetadata',
            [('id', item_id)])
        return response.get('getMediaMetadataResult', None)