def count_if(predicate, seq):
    """Count the number of elements of seq for which the predicate is true.
    >>> count_if(callable, [42, None, max, min])
    2
    """
    f = lambda count, x: count + (not not predicate(x))
    return reduce(f, seq, 0)
Count the number of elements of seq for which the predicate is true.
    >>> count_if(callable, [42, None, max, min])
    2