class Field

        def wrapped(*args, **kwargs):
            warnings.warn(
                "`%s.%s` is deprecated, use `%s` instead." %
                (self.class_name, self.old_method_name, self.new_method_name),
                self.deprecation_warning, 2)
            return f(*args, **kwargs)

    def bound_data(self, data, initial):
        """
        Return the value that should be shown for this field on render of a
        bound form, given the submitted POST data for the field and the initial
        data, if any.

        For most fields, this will simply be data; FileFields need to handle it
        a bit differently.
        """
        return data

    def clean(self, value):
        """
        Validates the given value and returns its "cleaned" value as an
        appropriate Python object.

        Raises ValidationError for any errors.
        """
        value = self.to_python(value)
        self.validate(value)
        self.run_validators(value)
        return value

    def has_changed(self, initial, data):
        """
        Return True if data differs from initial.
        """
        # For purposes of seeing whether something has changed, None is
        # the same as an empty string, if the data or initial value we get
        # is None, replace it w/ ''.
        initial_value = initial if initial is not None else ''
        try:
            data = self.to_python(data)
            if hasattr(self, '_coerce'):
                data = self._coerce(data)
        except ValidationError:
            return True
        data_value = data if data is not None else ''
        return initial_value != data_value

    def prepare_value(self, value):
        return value

    def run_validators(self, value):
        if value in self.empty_values:
            return
        errors = []
        for v in self.validators:
            try:
                v(value)
            except ValidationError as e:
                if hasattr(e, 'code') and e.code in self.error_messages:
                    e.message = self.error_messages[e.code]
                errors.extend(e.error_list)
        if errors:
            raise ValidationError(errors)

    def to_python(self, value):
        return value

    def validate(self, value):
        if value in self.empty_values and self.required:
            raise ValidationError(self.error_messages['required'], code='required')

    def widget_attrs(self, widget):
        """
        Given a Widget instance (*not* a Widget class), returns a dictionary of
        any HTML attributes that should be added to the Widget, based on this
        Field.
        """
        return {}