Return the field object with the given name (works for a bound instance)

def get_instance_field(self, field_name):
        """
        Return the field object with the given name (works for a bound instance)
        """
        if not self.has_field(field_name):
            raise AttributeError('"%s" is not a field for the model "%s"' %
                                 (field_name, self.__class__.__name__))

        field = getattr(self, field_name)

        return field