class_docstr: - FunctionType.inputs : A list of Type objects defining the types of the input
  - FunctionType.output: A Type object defining the type of the output
  - FunctionType.python_function : The original python function implementing
                                   this type. Two FunctionType objects compare
                                   equal only on inputs and output and not
                                   python_function
code: def __repr__(self):
      return (
          "("
          + ",".join(repr(x) for x in self.inputs)
          + ")->"
          + repr(self.output)
      )
  
file_path: coremltools/coremltools/converters/mil/mil/types/type_spec.py
label_desc: Use image node_id 4 for calling the FunctionType obj's underlying member method code with example usage: obj.__repr__() and returns: unknown