docs: def curve_points(self, beginframe, endframe, framestep, birthframe, startframe, stopframe, deathframe,
                       filternone=True, noiseframe=None):
          """
          returns a list of frames from startframe to stopframe, in steps of framestepj
          warning: the list of points may include "None" elements 
          :param beginframe: first frame to include in list of points
          :param endframe: last frame to include in list of points
          :param framestep: framestep 
          :param birthframe: frame before which animation always returns None
          :param startframe: frame from which animation starts to evolve 
          :param stopframe: frame in which animation completed
          :param deathframe: frame in which animation starts returning None 
          :param filternone: automatically remove None entries
          :param noiseframe: for time varying noise, this represents the time for which the noise should be evaluated
          :return: list of tweened values
          """
          if endframe < beginframe and framestep > 0:
              assert False, "infinite loop: beginframe = {0}, endframe = {1}, framestep = {2}".format(beginframe,
                                                                                                      endframe, framestep)
          if endframe > beginframe and framestep < 0:
              assert False, "infinite loop: beginframe = {0}, endframe = {1}, framestep = {2}".format(beginframe,
                                                                                                      endframe, framestep)
  
          i = beginframe
          result = [self.make_frame(i, birthframe, startframe, stopframe, deathframe, noiseframe)]
          while i < endframe:
              i += framestep
              if i <= endframe:
                  result.append(self.make_frame(i, birthframe, startframe, stopframe, deathframe, noiseframe))
          if filternone:
              return filter_none(result)
          else:
              return result