code: def calcCubicArcLengthC(pt1, pt2, pt3, pt4, tolerance=0.005):
      """Calculates the arc length for a cubic Bezier segment.
  
      Args:
          pt1,pt2,pt3,pt4: Control points of the Bezier as complex numbers.
          tolerance: Controls the precision of the calcuation.
  
      Returns:
          Arc length value.
      """
      mult = (
          1.0 + 1.5 * tolerance
      )  # The 1.5 is a empirical hack; no math
      return _calcCubicArcLengthCRecurse(mult, pt1, pt2, pt3, pt4)
  
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 4 for calling a global function with example usage: calcCubicArcLengthC(pt1, pt2, pt3, pt4, tolerance) and returns: _calcCubicArcLengthCRecurse