subprocess_server.py fails to find a free port in IPv6 only environment

../apache_beam/utils/subprocess_server.py", line 294, in find_free_port
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  File "<embedded stdlib>/socket.py", line 144, in __init__
    _socket.socket.__init__(self, family, type, proto, fileno)
OSError: [Errno 97] Address family not supported by protocol