FastMarchingDistanceGrid fails with NameError: name 'GridSlice' is not defined

[jjrob]

Full traceback:

  File "C:\Users\jjr8\AppData\Local\ESRI\conda\envs\arcgispro-py3-denmod\Lib\site-packages\GeoEco\Datasets\_Grid.py", line 744, in _GetUnscaledDataAsArray
    data, actualNoDataValue = self._ReadNumpyArray(reorderedSliceList)
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\jjr8\AppData\Local\ESRI\conda\envs\arcgispro-py3-denmod\Lib\site-packages\GeoEco\Datasets\Virtual\_FastMarchingDistanceGrid.py", line 160, in _ReadNumpyArray
    grid = GridSlice(self._Grid, tIndex=s[0])
           ^^^^^^^^^
NameError: name 'GridSlice' is not defined