#NEWLINE# def __init__( self , slug_field = 'slug' , product_field = 'product' , **kwargs ) : #NEWLINE# #INDENT# super ( TopicField , self ) . __init__ ( slug_field = slug_field , ** kwargs ) #NEWLINE# self . product_field = product_field #NEWLINE# self . error_messages [ 'missing_product' ] = 'A product must be specified to select a topic.'