code: def convert_data_type(data_type):
      if data_type == "points":
          return c_size_t(0)
      elif data_type == "distance_matrix":
          return c_size_t(1)
      else:
          raise TypeError(
              "Unknown data type is specified '%s'." % data_type
          )
  
label_desc: Use image node_id 1 for calling a global function with example usage: convert_data_type(data_type) and returns: c_size_t, c_size_t