code: def vector_sin(self, vec):
      assert len(vec) == 2
      return vec[1] / (norm(vec) + self.eps)
  
imports: import cv2
  import numpy
  from ppocr.utils.utility import check_install
  from numpy.linalg import norm
label_desc: Use image node_id 4 for calling the DRRGTargets obj's underlying member method code with example usage: obj.vector_sin(vec) and returns: unknown