code: def _get_value_to_set_at_point(self, point):
          
          laste, lastv = None, None
          for e, v in self.schedule:
              if e == point:
                  return v    # meet the exact boundary, return directly
              if e > point:
                  break
              laste, lastv = e, v
          if laste is None or laste == e:
              # hasn't reached the first scheduled point, or reached the end of all scheduled points
              return None
          if self.interp is None:
              # If no interpolation, nothing to do.
              return None
          v = (point - laste) * 1. / (e - laste) * (v - lastv) + lastv
          return v
docs: Using schedule, compute the value to be set at a given point.