def IN1(a, b):
    """
    >>> IN1(1, [1,2,3])
    True
    >>> IN1([1,2,3], 1)
    False
    >>> IN1(1, [2,3])
    False
    >>> IN1("abc", "hello abc world")
    True
    >>> IN1("xyz", "hello abc world")
    False
    """
    try:
        return a in b
    except TypeError:
        return False