code: def get_py_files(dir_name: str) -> list:
      
      return flatten([
          x for x in
          [["{0}/{1}".format(path, f) for f in files if f.endswith(".py")]
           for path, _, files in os.walk(dir_name)
           if not path.startswith("./build")] if x
      ])
docs: Get all .py files.