def sigma_exp(p, q):
 q1 = q[0]
 q2 = q[1]
 return ((((C_exp - delta(p, q1)) - delta(p, q2)) - V(p)) - max(V(q1), V(q2)))

def sigma_exp ( p , q ) : q1 = q [ 0 ] q2 = q [ 1 ] return ( ( ( ( C_exp - delta ( p , q1 ) ) - delta ( p , q2 ) ) - V ( p ) ) - max ( V ( q1 ) , V ( q2 ) ) )
returns score of an expansion/compression .