Returns a TupleErrorList for this field. This overloaded method adds additional error lists
        to the errors as detected by the form validator.

def errors(self):
        """
        Returns a TupleErrorList for this field. This overloaded method adds additional error lists
        to the errors as detected by the form validator.
        """
        if not hasattr(self, '_errors_cache'):
            self._errors_cache = self.form.get_field_errors(self)
        return self._errors_cache