'Saves this ``form``\'s cleaned_data into model instance
``self.instance``.
If commit=True, then the changes to ``instance`` will be saved to the
database. Returns ``instance``.'

def save(self, commit=True):

    if (self.instance.pk is None):
        fail_message = u'created'
    else:
        fail_message = u'changed'
    return save_instance(self, self.instance, self._meta.fields, fail_message, commit, construct=False)
