code: def calcCubicParametersC(pt1, pt2, pt3, pt4):
      c = (pt2 - pt1) * 3.0
      b = (pt3 - pt2) * 3.0 - c
      a = pt4 - pt1 - c - b
      return (a, b, c, pt1)
  
imports: from fontTools.misc.arrayTools import calcBounds, sectRect, rectArea
  from fontTools.misc.transform import Identity
  import math
  from collections import namedtuple
  from math import sqrt, acos, cos, pi
label_desc: Use image node_id 29 for calling a global function with example usage: calcCubicParametersC(pt1, pt2, pt3, pt4) and returns: a,  b,  c,  pt1