code: def _read_import_root_map_file(path):
      
      if os.path.exists(path):
        with open(path, 'r') as fp:
          return dict({import_path: root for import_path, root in
                       (x.strip().split('\t') for x in fp.readlines())})
      else:
        return {}
docs: Reads a file mapping import paths to roots (e.g., example.org/pkg/foo -> example.org).