code: def _alignment_transformation(segment):
      # Returns a transformation which aligns a segment horizontally at the
      # origin. Apply this transformation to curves and root-find to find
      # intersections with the segment.
      start = segment[0]
      end = segment[-1]
      angle = math.atan2(end[1] - start[1], end[0] - start[0])
      return Identity.rotate(-angle).translate(-start[0], -start[1])
  
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 41 for calling a global function with example usage: _alignment_transformation(segment) and returns: Identity