numpy.float64 object cannot be interpreted as an index

[FilipDominec]

Simulations in the example_metamaterial_s_parameters/SphereWire_principles terminate with error

Traceback (most recent call last):
  File "../../scatter.py", line 113, in <module>
    eps1=getattr(model, 'mon1eps', 1), eps2=getattr(model, 'mon2eps', 1))               ## enable monitors inside dielectrics
  File "/home/dominecf/python-meep-utils/meep_utils.py", line 902, in get_s_parameters
    Ex1, Hy1, Ex2, Hy2  =  map(lambda x: np.append(x, np.zeros(target_len - len(Ex1))), (Ex1, Hy1, Ex2, Hy2))
  File "/home/dominecf/python-meep-utils/meep_utils.py", line 902, in <lambda>
    Ex1, Hy1, Ex2, Hy2  =  map(lambda x: np.append(x, np.zeros(target_len - len(Ex1))), (Ex1, Hy1, Ex2, Hy2))
TypeError: 'numpy.float64' object cannot be interpreted as an index

However, the FDTD computation finishes correctly, as seen from the plotted E-field curve.