code: def attach_files(self, files: Sequence[AttachedFile]):
          '''
          Attach a list of files represented as AttachedFile.
          '''
          assert not self._content, 'content must be empty to attach files.'
          self.content_type = 'multipart/form-data'
          self._attached_files = filef attach_files(self, files: Sequence[AttachedFile]):
          '''
          Attach a list of files represented as AttachedFile.
          '''
          assert not self._content, 'content must be empty to attach files.'
          self.content_type = 'multipart/form-data'
          self._attached_files = files
docs: Attach a list of files represented as AttachedFile.