@sig(["a"]/ H[(Eq, "a")] >> [["a"]])
def group(xs):
    """
    group :: Eq a => [a] -> [[a]]

    The group function takes a list and returns a list of lists such that the
    concatenation of the result is equal to the argument. Moreover, each
    sublist in the result contains only equal elements.
    It is a special case of groupBy, which allows the programmer to supply
    their own equality test.
    """
    return groupBy(xs, (__==__))
dataset/ETHPy150Open billpmurphy/hask/hask/Data/List.py/group/swapped operands of `/`