Fix sim.py tab error that causes test fail in Python 3
Fix sim.py tab error that causes test fail in Python 3

fangohr/oommf-python,ryanpepper/oommf-python,fangohr/oommf-python,fangohr/oommf-python,ryanpepper/oommf-python,ryanpepper/oommf-python,ryanpepper/oommf-python