def euclidian_distance(a, b):
    """
    Calculating Euclidian distance between 2 vectors
    :param a: 1st vector
    :param b: 2nd vector
    :return:
    """
    assert len(a) == len(b)
    d = 0
    for feature in range(len(a)):
        d += (a[feature] - b[feature]) ** 2

    return d ** 0.5