code: def initialize_fields(self, content):
          
          for name, value in content.items():
              if name is 'value':
                  self.value = value
              elif name is 'data':
                  # Container or Pointer
                  if is_mixin(self._data):
                      self._data.initialize_fields(value)
                  # Field
                  elif is_field(self._data):
                      self._data.value = value
docs: Initializes the `Pointer` field itself and the :class:`Field` items
          in the :attr:`data` object referenced by the `Pointer` field with the
          *values* in the *content* dictionary.
  
          The ``['value']`` key in the *content* dictionary refers to the `Pointer`
          field itself and the ``['data']`` key refers to the :attr:`data` object
          referenced by the `Pointer` field.
  
          :param dict content: a dictionary contains the :class:`~Field.value`
              for the `Pointer` field and the :class:`~Field.value` for each
              :class:`Field` in the :attr:`data` object referenced by the
              `Pointer` field.