In [1]:
import py3Dmol
bohr = open('../tests/auto/data/bohr.cube').read()
p = py3Dmol.view()
p.addVolumetricData(bohr, "cube", {'isoval': -0.01, 'color': "red", 'opacity': 0.95})
p.zoomTo();
p.show()

You appear to be running in JupyterLab (or JavaScript failed to load for some other reason). You need to install the 3dmol extension:
jupyter labextension install jupyterlab_3dmol