nodes: 0, module; 1, function_definition; 2, function_name:_listChunks; 3, parameters; 4, block; 5, identifier:self; 6, expression_statement; 7, expression_statement; 8, for_statement; 9, return_statement; 10, comment:"""
          Lists stored chunks
  
          :return: sorted list of available chunk indices
          """; 11, assignment; 12, identifier:fileName; 13, call; 14, block; 15, call; 16, identifier:chunks; 17, list; 18, attribute; 19, argument_list; 20, expression_statement; 21, if_statement; 22, identifier:sorted; 23, argument_list; 24, identifier:os; 25, identifier:listdir; 26, attribute; 27, assignment; 28, comparison_operator:index is not None; 29, block; 30, identifier:chunks; 31, identifier:self; 32, identifier:dataDir; 33, identifier:index; 34, call; 35, identifier:index; 36, None; 37, expression_statement; 38, attribute; 39, argument_list; 40, call; 41, identifier:ChunkedFileStore; 42, identifier:_fileNameToChunkIndex; 43, identifier:fileName; 44, attribute; 45, argument_list; 46, identifier:chunks; 47, identifier:append; 48, identifier:index
code: def _listChunks(self):
          """
          Lists stored chunks
  
          :return: sorted list of available chunk indices
          """
          chunks = []
          for fileName in os.listdir(self.dataDir):
              index = ChunkedFileStore._fileNameToChunkIndex(fileName)
              if index is not None:
                  chunks.append(index)
          return sorted(chunks)