code: def get_container_id(self, container_id=None):
          ''' a helper function shared between functions that will return a 
              container_id. First preference goes to a container_id provided by
              the user at runtime. Second preference goes to the container_id
              instantiated with the client.
  
              Parameters
              ==========
              container_id: image uri to parse (required)
          '''
  
          # The user must provide a container_id, or have one with the client
          if container_id == None and self.container_id == None:
              bot.exit('You must provide a container_id.')
  
          # Choose whichever is not None, with preference for function provided
          container_id = container_id or self.container_id
          return container_if get_container_id(self, container_id=None):
          ''' a helper function shared between functions that will return a 
              container_id. First preference goes to a container_id provided by
              the user at runtime. Second preference goes to the container_id
              instantiated with the client.
  
              Parameters
              ==========
              container_id: image uri to parse (required)
          '''
  
          # The user must provide a container_id, or have one with the client
          if container_id == None and self.container_id == None:
              bot.exit('You must provide a container_id.')
  
          # Choose whichever is not None, with preference for function provided
          container_id = container_id or self.container_id
          return container_id
docs: a helper function shared between functions that will return a 
              container_id. First preference goes to a container_id provided by
              the user at runtime. Second preference goes to the container_id
              instantiated with the client.
  
              Parameters
              ==========
              container_id: image uri to parse (required)