code: def do_close(self, args):
          
  
          if not self.current:
              print('There are no resources in use. Use the command "open".')
              return
  
          try:
              self.current.close()
          except Exception as e:
              print(e)
          else:
              print('The resource has been closed.')
              self.current = None
              self.prompt = self.default_prompt
docs: Close resource in use.