code: def tool(name):
      # type: (str) -> FunctionType
      
      global g_tools
  
      def decorator(fn):  # pylint: disable=missing-docstring
          # type: (FunctionType) -> FunctionType
          g_tools[name] = fn
          return fn
  
      return decorator
docs: Decorator for defining lint tools.
  
      Args:
          name (str):
              The name of the tool. This name will be used to identify the tool
              in `pelconf.yaml`.