fields.py 文件源码

def _coerce(self, value):
        """
        Validates that the values are in self.choices and can be coerced to the
        right type.
        """
        if value == self.empty_value or value in self.empty_values:
            return self.empty_value
        new_value = []
        for choice in value:
            try:
                new_value.append(self.coerce(choice))
            except (ValueError, TypeError, ValidationError):
                raise ValidationError(
                    self.error_messages['invalid_choice'],
                    code='invalid_choice',
                    params={'value': choice},
                )
        return new_value