docs: def create_global_step(session: tf.Session) -> tf.Variable:
      """
      Creates the Tensorflow 'global_step' variable (see `MonitorContext.global_step_tensor`).
      :param session: Tensorflow session the optimiser is running in
      :return: The variable tensor.
      """
      global_step_tensor = tf.Variable(0, trainable=False, name="global_step")
      session.run(global_step_tensor.initializer)
      return global_step_tensor