def __init__(self, half_edge):
    assert half_edge.is_hexagonal
    if (half_edge.color is not 'black'):
        half_edge = half_edge.opposite.next
    assert (half_edge.color is 'black')
    super(IrreducibleDissection, self).__init__(half_edge)
def __init__(self, half_edge):
    assert half_edge.is_hexagonal
    if (half_edge.color is not 'black'):
        half_edge = half_edge.opposite.next
    assert (half_edge.color is 'black')
    super(IrreducibleDissection, self).__init__(half_edge)