euclidian

def euclidian(a, b):
    """
    Calculate distance between points on 2d surface
    :param a: a list of coordinates for point a
    :param b: a list of coordinates for point b
    :return: distance in whichever unit is provided to the function
    """

    x1 = a[0]
    y1 = a[1]

    x2 = b[0]
    y2 = b[1]

    a = np.array((x1, y1))
    b = np.array((x2, y2))

    dist = np.linalg.norm(a - b)

    return dist