deltacube2 for key value in zcube2dict items if func1 key key if func1

deltacube2 = 0.0
for key, value in zcube2dict.items():
    if (func1(key[0], key[1]) == 0):
        if ((func1(key[0], key[1]) - value) == 0):
            deltacube2 += 0.0
        else:
            print "denom is zero but nom is not zero: ", (func1(key[0], key[1]) - value)
    else:
        plval = np.fabs((func1(key[0], key[1]) - value)/func1(key[0], key[1]))
        #print plval
        deltacube2 += plval

deltacube2 = deltacube2/len(zcube2dict)