#NEWLINE# def create_model_reference( model_instance ) : #NEWLINE# #INDENT# '\n    creates a reference to a model instance that can be stored in activities\n\n    >>> from core.models import Like\n    >>> like = Like.object.get(id=1)\n    >>> create_reference(like)\n    core.Like:1\n\n    ' #NEWLINE# content_type = model_content_type ( model_instance . __class__ ) #NEWLINE# content_id = model_instance . pk #NEWLINE# return ( '%s:%s' % ( content_type , content_id ) )