text: import os
  import subprocess
  
  import click
  
  controllers = []
  
  
  @click.group()
  def cli():
      """Manage SDN Controller"""
      pass
  
  
  @click.command()
  def ls():
      """
      Lists the connected SDN controllers
      """
  
      for sdn_con in controllers:
          click.echo("{0} controller @ {1}".format(sdn_con["type"], sdn_con["ip"]))
  
  
  cli.add_command(ls)
  