def dot_arc(a, label, b):
    assert u" " not in a and u" " not in b
    assert a + label + b not in u"\n"
    return u"{0} -> {1} [label=\"{2}\"];\n".format(a, b, label)
dataset/ETHPy150Open machinalis/quepy/quepy/dot_generation.py/dot_arc/swapped operands of `not in`