code: def on_timer(self, event):
      self.theta += 0.25
      self.phi += 0.25
      self.model = np.dot(
          rotate(self.theta, (0, 0, 1)), rotate(self.phi, (0, 1, 0))
      )
      self.program["u_model"] = self.model
      self.update()
  
file_path: vispy/examples/demo/gloo/molecular_viewer.py
imports: import numpy
  from vispy import gloo
  from vispy import app
  from vispy.util.transforms import perspective, translate, rotate
  from vispy.io import load_data_file
label_desc: Use image node_id 5 for calling the Canvas obj's underlying member method code with example usage: obj.on_timer(event) without return types