code: def rot_points(pnts, pb, alfa):
      
      points = []                   # rotated points
      calfa = math.cos(alfa)
      salfa = math.sin(alfa)
      for p in pnts:
          s = p - pb
          r = abs(s)
          if r > 0: s /= r
          np = (s.x * calfa - s.y * salfa, s.y * calfa + s.x * salfa)
          points.append(pb + fitz.Point(np)*r)
      return points
docs: Rotate a list of points by an angle alfa (radians) around pivotal point pb.
      Intended for modifying the control points of trigonometric functions.