code: def my_callback() -> None:
      print("Hello, GPflow monitoring!")
  
file_path: GPflow/notebooks/getting_started/monitoring.pct.py
imports: import os
  import warnings
  import matplotlib
  import matplotlib.pyplot
  import numpy
  import tensorflow
  import gpflow
label_desc: Use image node_id 2 for calling a global function with example usage: my_callback() without return types