code: def add_nodes(self, coors, node_low_or_high=None):
          
          last = self.lastnode
          if type(coors) is nm.ndarray:
              if len(coors.shape) == 1:
                  coors = coors.reshape((1, coors.size))
  
              nadd = coors.shape[0]
              idx = slice(last, last + nadd)
          else:
              nadd = 1
              idx = self.lastnode
          right_dimension = coors.shape[1]
          self.nodes[idx, :right_dimension] = coors
          self.node_flag[idx] = True
          self.lastnode += nadd
          self.nnodes += nadd
docs: Add new nodes at the end of the list.