code: def to_vw_example_format(
      self, context, actions, cb_label=None, ns1="U", ns2="A"
  ):
      if ns1 == ns2:
          raise ("not allowed to have same namespace")
  
      if cb_label is not None:
          chosen_action, cost, prob = cb_label
          self.other_index_count.update(((chosen_action, prob),))
      example_string = ""
      example_string += f'shared |{ns1}ser user={context["user"]} time_of_day={context["time_of_day"]}\n'
      for action in actions:
          if cb_label is not None and action == chosen_action:
              example_string += "0:{}:{} ".format(cost, prob)
          example_string += f"|{ns2}ction article={action} \n"
      # Strip the last newline
      return example_string[:-1]
  
imports: import vowpalwabbit
  from distributionally_robust_data import OnlineCressieRead
  import collections
  import os
  import random
  import os
label_desc: Use image node_id 3 for calling the Simulator obj's underlying member method code with example usage: obj.to_vw_example_format(context, actions, cb_label, ns1, ns2) and returns: example_string