def _has_vector_data(object):
    data_sources = get_vtk_src(object)
    for source in data_sources:
        if source.point_data.vectors is not None:
            return True
        elif source.cell_data.vectors is not None:
            return True
    return False
Verify that value is True, False, 0, or 1
dataset/ETHPy150Open enthought/mayavi/mayavi/tools/tools.py/_has_vector_data--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/setuptools-0.6c11/setuptools/dist.py/assert_bool