pants.engine.exp.objects.SerializationError: Failed to pickle Return(value=AddressFamily(namespace='3rdparty/python', objects_by_name=['setproctitle', 'pystache', 'zincutils', 'pex', 'psutil', 'pywatchman', 'six', 'docutils', 'pytest', 'pathspec', 'lmdb', 'mock', 'wheel', 'mox', 'coverage', 'antlr-3.1.3', 'beautifulsoup4', 'lockfile', 'thrift', 'Markdown', 'pyflakes', 'pytest-cov', 'pep8', 'Pygments', 'setuptools', 'ansicolors', 'requests'])): can't pickle function objects