code: def tween(self, t):
          
          if t is None:
              return None
  
          if self.method in self.method_to_tween:
              return self.method_to_tween[self.method](t)
          elif self.method in self.method_1param:
              return self.method_1param[self.method](t, self.param1)
          elif self.method in self.method_2param:
              return self.method_2param[self.method](t, self.param1, self.param2)
          else:
              raise Exception("Unsupported tween method {0}".format(self.method))
docs: t is number between 0 and 1 to indicate how far the tween has progressed