code: def normalized(self, document, schema=None, always_return_document=False):
          
          self.__init_processing(document, schema)
          self.__normalize_mapping(self.document, self.schema)
          self.error_handler.end(self)
          if self._errors and not always_return_document:
              return None
          else:
              return self.document
docs: Returns the document normalized according to the specified rules
          of a schema.
  
          :param document: The document to normalize.
          :type document: any :term:`mapping`
          :param schema: The validation schema. Defaults to :obj:`None`. If not
                         provided here, the schema must have been provided at
                         class instantiation.
          :type schema: any :term:`mapping`
          :param always_return_document: Return the document, even if an error
                                         occurred. Defaults to: ``False``.
          :type always_return_document: :class:`bool`
          :return: A normalized copy of the provided mapping or :obj:`None` if an
                   error occurred during normalization.