docs: def _inner_read_config(path):
      '''
      Helper to read a named config file.
      The grossness with the global is a workaround for this python bug:
      https://bugs.python.org/issue21591
      The bug prevents us from defining either a local function or a lambda
      in the scope of read_fbcode_builder_config below.
      '''
      global _project_dir
      full_path = os.path.join(_project_dir, path)
      return read_fbcode_builder_config(full_path)