@sig(H[(Eq, "a")]/ "a" >> ["a"] >> bool)
def elem(x, xs):
    """
    elem :: Eq a => a -> [a] -> Bool

    elem is the list membership predicate, elem(x, xs). For the result to be
    False, the list must be finite; True, however, results from an element
    equal to x found at a finite index of a finite or infinite list.
    """
    return x in xs
dataset/ETHPy150Open billpmurphy/hask/hask/Data/List.py/elem/original