Marabou NNet Example unhashable type: 'numpy.ndarray'

Question

I'm trying out Marabou tool and the provided examples in https://neuralnetworkverification.github.io/Marabou/Examples/0_NNetExample.html

The NNet Example throws the following error. How could that be fixed?

Traceback (most recent call last):

  File "0_NNetExample.py", line 35, in <module>

    net1.setLowerBound(net1.outputVars[0][0], .5)

  File "/home/user/verification/Marabou/maraboupy/MarabouNetwork.py", line 99, in setLowerBound

    self.lowerBounds[x]=v

TypeError: unhashable type: 'numpy.ndarray'

An expected behavior is the executed .py .