def circle_distance(circle_i, circle_j):
    """
    Function for calculating the distance
    between the two circles.
    """
    cy_i, cx_i, rad_i, accum_i = circle_i
    cy_j, cx_j, rad_j, accum_j = circle_j
    distance = ((cy_i-cy_j)**2 + (cx_i-cx_j)**2)**.5
    return distance