Power space not working in more than 2 dim.

For changes in demos/wiener_filter_via_curvature.py of the dimension from 2 to 3 comes the error:

Traceback (most recent call last):
  File "wiener_filter_via_curvature.py", line 43, in <module>
    power_space = ift.PowerSpace(harmonic_space)
  File "/home/philipp/.local/lib/python3.6/site-packages/nifty4-3.9.0-py3.6.egg/nifty4/spaces/power_space.py", line 139, in __init__
  File "/home/philipp/.local/lib/python3.6/site-packages/nifty4-3.9.0-py3.6.egg/nifty4/spaces/rg_space.py", line 93, in get_k_length_array
  File "/home/philipp/.local/lib/python3.6/site-packages/nifty4-3.9.0-py3.6.egg/nifty4/field.py", line 77, in __init__
MemoryError

What is wrong here?