#NEWLINE# def items_from_user( self , user_id ) : #NEWLINE# #INDENT# '\n        Returns\n        -------\n        items_from_user : numpy array of shape [item_id,..]\n                 Return IDs of items user expresses a preference for\n        ' #NEWLINE# preferences = self . preferences_from_user ( user_id ) #NEWLINE# return [ key for ( key , value ) in preferences ]