There is a cyclic import in dmprof

tools/deep_memory_profiler/lib/subcommand.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import logging
 import optparse
 import os
 import re
 
 from lib.bucket import BucketSet
-from lib.dump import Dump, DumpList
+from lib.dump import Dump
+from lib.dumplist import DumpList
 from lib.symbol import SymbolDataSources, SymbolMappingCache, SymbolFinder
 from lib.symbol import procfs
 from lib.symbol import FUNCTION_SYMBOLS, SOURCEFILE_SYMBOLS, TYPEINFO_SYMBOLS
 
 
 LOGGER = logging.getLogger('dmprof')
 
 BASE_PATH = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 CHROME_SRC_PATH = os.path.join(BASE_PATH, os.pardir, os.pardir)
 
@@ skipping 125 matching lines @@
       self._parser.error('needs %d argument(s).\n' % required)
       return None
     return (options, args)
 
   @staticmethod
   def _parse_policy_list(options_policy):
     if options_policy:
       return options_policy.split(',')
     else:
       return None