在进行SCON以构建gem5时，没有名为“six”的模块

Question

~/Documents/gem5$ scons build/ARM/gem5.opt -j 4
scons: Reading SConscript files ...
ModuleNotFoundError: No module named 'six':
  File "/Users/anuragkar/Documents/gem5/SConstruct", line 100:
    from m5.util import compareVersions, readCommand, readCommandWithReturn
  File "/Users/anuragkar/Documents/gem5/src/python/m5/util/__init__.py", line 46:
    from six import string_types

我在python2.7和python3上都安装了六个，但是这个错误不断出现。我尝试在python2.7和python3 shell上执行“ImportSix”，效果很好。这里真的很无聊