code: def is_installable_dir(path):
      # type: (str) -> bool
      
      if not os.path.isdir(path):
          return False
      setup_py = os.path.join(path, 'setup.py')
      if os.path.isfile(setup_py):
          return True
      pyproject_toml = os.path.join(path, 'pyproject.toml')
      if os.path.isfile(pyproject_toml):
          return True
      return False
docs: Is path is a directory containing setup.py or pyproject.toml?