code: def check_if_single_file(client, fileshare, prefix, timeout=None):
      # type: (azure.storage.file.FileService, str, str, int) ->
      #        Tuple[bool, azure.storage.file.models.File]
      
      if blobxfer.util.is_none_or_empty(prefix):
          return (False, None)
      file = get_file_properties(client, fileshare, prefix, timeout)
      if file is None:
          return (False, file)
      else:
          return (True, file)
docs: Check if prefix is a single file or multiple files
      :param FileService client: blob client
      :param str fileshare: file share name
      :param str prefix: path prefix
      :param int timeout: timeout
      :rtype: tuple
      :return: (if prefix in fileshare is a single file, file)