code: def print_prompt(prompt,msg_id=None):
      
      global show_execution_count
      if show_execution_count and msg_id:
          # wait to get message back from kernel
          try:
              child = get_child_msg(msg_id)
              count = child['content']['execution_count']
              echo("In[%d]: %s" %(count,prompt))
          except Empty:
              echo("In[]: %s (no reply from IPython kernel)" % prompt)
      else:
          echo("In[]: %s" % prompt)
docs: Print In[] or In[42] style messages