input: 
  def simple_chatbot_state_transitions(current_state: dict, user_input: str) -> dict:
      """
      Update the current state of a simple chatbot based on the user input. The chatbot uses state diagrams
      to manage conversation flow, and each state has a predefined set of replies that lead to different states.
      If the user input does not match any of the predefined replies in the current state, print a message
      indicating that the input is not understood and return the current state unchanged.
      If the user input matches a valid reply in the current state, update the state to the corresponding state.
      If the current state has no replies, print "Goodbye!" and end the conversation.
  
      >>> simple_chatbot_state_transitions(state0, 'I need some advice')
      state1
      >>> simple_chatbot_state_transitions(state2, 'Where can I find good tutorials')
      state5
      >>> simple_chatbot_state_transitions(state0, 'Hello!')
      I don't understand what you mean. Please try again.
      state0
      """
      if user_input in current_state['replies']:
          return eval(current_state['replies'][user_input])
      else:
          print("I don't understand what you mean. Please try again.")
          return current_state
  
output:     
      if not current_state['replies']:
          print("Goodbye!")
          return current_state
  