def listpack(x):
    """
    >>> listpack(1)
    [1]
    >>> listpack((1, 2))
    [1, 2]
    >>> listpack([1, 2])
    [1, 2]
    """
    if isinstance(x, tuple):
        return list(x)
    elif isinstance(x, list):
        return x
    else:
        return [x]