@sig(["a"]/ H >> [["a"]] >> ["a"] )
def intercalate(xs, xss):
    """
    intercalate :: [a] -> [[a]] -> [a]

    intercalate(xs,xss) is equivalent to concat(intersperse(xs,xss)). It
    inserts the list xs in between the lists in xss and concatenates the
    result.
    """
    return concat(intersperse(xs, xss))
dataset/ETHPy150Open billpmurphy/hask/hask/Data/List.py/intercalate/swapped operands of `/`