code: def triangulate_quads(quads):
      
      if len(quads) == 0:
          return quads
      quads = np.asanyarray(quads)
      faces = np.vstack((quads[:, [0, 1, 2]],
                         quads[:, [2, 3, 0]]))
      return faces
docs: Given a set of quad faces, return them as triangle faces.
  
      Parameters
      -----------
      quads: (n, 4) int
        Vertex indices of quad faces
  
      Returns
      -----------
      faces : (m, 3) int
        Vertex indices of triangular faces