Windows 10 x64 psscan error: ^: 'int' and 'NoneType' #436

$ python vol.py -f Windows\ 10\ x64-c4aa8f1b.vmem --profile=Win10x64_14393 psscan
Volatility Foundation Volatility Framework 2.6
Offset(P)          Name                PID   PPID PDB
Time created                   Time exited
------------------ ---------------- ------ ------ ------------------
------------------------------ ------------------------------
WARNING : volatility.debug    : Cannot find nt!ObGetObjectType
WARNING : volatility.debug    : Cannot find nt!ObGetObjectType
Traceback (most recent call last):
  File "vol.py", line 192, in <module>
    main()
  File "vol.py", line 183, in main
    command.execute()
  File "volatility/volatility/commands.py", line 147, in execute
    func(outfd, data)
  File "volatility/volatility/plugins/filescan.py", line 423, in render_text
    for eprocess in data:
  File "volatility/volatility/poolscan.py", line 252, in scan
    skip_type_check = skip_type_check)
  File "volatility/volatility/plugins/overlays/windows/windows.py", line
1144, in get_object
    return self.get_object_top_down(struct_name, object_type,
skip_type_check)
  File "volatility/volatility/plugins/overlays/windows/windows.py", line
1117, in get_object_top_down
    header.get_object_type() == object_type):
  File "volatility/volatility/plugins/overlays/windows/win7.py", line
155, in get_object_type
    return self.type_map.get(int(self.TypeIndex), '')
  File "volatility/volatility/plugins/overlays/windows/win10.py", line
279, in TypeIndex
    return ((addr >> 8) ^ cook ^ indx) & 0xFF
TypeError: unsupported operand type(s) for ^: 'int' and 'NoneType'