def compact(a):
    return [b for b in a if b is not None]
Test if points can be looked up with both int and long keys.
dataset/ETHPy150Open heiskr/sagefy/server/modules/util.py/compact--crossover with--dataset/ETHPy150Open enthought/mayavi/tvtk/tests/test_tvtk.py/TestTVTK.test_points_lookup