def prepend_model(self, value, model):
if '<STR_LIT:.>' not in value:<EOL><INDENT>direction = '<STR_LIT>'<EOL>if value.startswith('<STR_LIT:->'):<EOL><INDENT>value = value[<NUM_LIT:1>:]<EOL>direction = '<STR_LIT:->'<EOL><DEDENT>value = '<STR_LIT>' % (direction, model, value)<EOL><DEDENT>return value<EOL>
Prepends model name if it is not already prepended.
For example model is "Offer":

    key -> Offer.key
    -key -> -Offer.key
    Offer.key -> Offer.key
    -Offer.key -> -Offer.key