def distance(x,y):
    """[summary]
    HELPER-FUNCTION
    calculates the (eulidean) distance between vector x and y.

    Arguments:
        x {[tuple]} -- [vector]
        y {[tuple]} -- [vector]
    """
    assert len(x) == len(y), "The vector must have same length"
    result = ()
    sum = 0
    for i in range(len(x)):
        result += (x[i] -y[i],)
    for component in result:
        sum += component**2
    return math.sqrt(sum)