code: def _unit_vector(vec):
      length = hypot(*vec)
      if length == 0:
          return None
      return (vec[0] / length, vec[1] / length)
  
file_path: catboost/contrib/python/fonttools/fontTools/colorLib/geometry.py
imports: from math import copysign, cos, hypot, isclose, pi
  from fontTools.misc.roundTools import otRound
label_desc: Use image node_id 3 for calling a global function with example usage: _unit_vector(vec) and returns: unknown,  unknown, None