code: def from_python_file(
          cls, python_file, lambdas_path, json_filename: str, stem: str
      ):
          
          with open(python_file, "r") as f:
              pySrc = f.read()
          return cls.from_python_src(pySrc, lambdas_path, json_filename, stem)
docs: Builds GrFN object from Python file.