class Fibonacci: def __init__(self, start: int): if start<0: raise ValueError("Starting ... code is running in regular Python mode or compiled Cython mode. An example: if cython.compiled: data ...

In Python, sys.stdin is a read-only file object ... you can use the as part of the with statement. For example: def test_double_str(monkeypatch): with pytest.raises(ValueError) as e: ...