docs: def get_frame_src(f:Frame) -> str:
      ''' inspects a frame and returns a string with the following
  
          <src-path>:<src-line> -> <function-name>
          <source-code>
      '''
      path, line, src, fn = _get_frame(
          inspect.getframeinfo(f)
      )
      return '{}:{} -> {}\n{}'.format(
          path.split(os.sep)[-1],
          line,
          fn,
          repr(src[0][:-1]) # shave off \n
      )