code: def _GetDataTypeMap(self, name):
      
      data_type_map = self._data_type_maps.get(name, None)
      if not data_type_map:
        data_type_map = self._fabric.CreateDataTypeMap(name)
        self._data_type_maps[name] = data_type_map
  
      return data_type_map
docs: Retrieves a data type map defined by the definition file.
  
      The data type maps are cached for reuse.
  
      Args:
        name (str): name of the data type as defined by the definition file.
  
      Returns:
        dtfabric.DataTypeMap: data type map which contains a data type definition,
            such as a structure, that can be mapped onto binary data.