def checkCalcForceExertedBy(self): print("Checking calcForceExertedBy...") p1 = Planet(1.0, 1.0, 3.0, 4.0, 5.0, "jupiter.gif") p2 = Planet(2.0, 1.0, 3.0, 4.0, 4e11, "jupiter.gif") p3 = Planet(4.0, 5.0, 3.0, 4.0, 5.0, "jupiter.gif") print(Planet.G) self.checkEquals(p1.calcForceExertedBy(p2), 133.4, "calcForceExertedBy()", 0.01) self.checkEquals(p1.calcForceExertedBy(p3), 6.67e-11, "calcForceExertedBy()", 0.01)