docs: def find_resource(r, *, pkg='cyther'):
      """
      Finds a given cyther resource in the 'test' subdirectory in
      'cyther' package
      """
      file_path = pkg_resources.resource_filename(pkg, os.path.join('test', r))
      if not os.path.isfile(file_path):
          msg = "Resource '{}' does not exist"
          raise FileNotFoundError(msg.format(file_path))
      return file_path