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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def circumcircle_radius_2(pt0, pt1, pt2):
 r"""Calculate and return the squared radius of a given triangle's circumcircle. This is faster than calculating radius but should only be used with comparable ratios. Parameters pt0: (x, y) Starting vertex of triangle pt1: (x, y) Second vertex of triangle pt2: (x, y) Final vertex of a triangle Returns ------- r: float circumcircle radius See Also -------- circumcenter """

    a = distance(pt0, pt1)
    b = distance(pt1, pt2)
    c = distance(pt2, pt0)

    t_area = triangle_area(pt0, pt1, pt2)
    prod2 = a * b * c

    if t_area > 0:
        radius = prod2 * prod2 / (16 * t_area * t_area)
    else:
        radius = np.nan

    return radius