code: def media_update(self, id, description=None, focus=None):
          
          id = self.__unpack_id(id)
  
          if focus != None:
              focus = str(focus[0]) + "," + str(focus[1])
              
          params = self.__generate_params(locals(), ['id'])  
          return self.__api_request('PUT', '/api/v1/media/{0}'.format(str(id)), params)
docs: Update the metadata of the media file with the given `id`. `description` and 
          `focus` are as in `media_post()`_ .
          
          Returns the updated `media dict`_.