code: def bash_complete_command(app_name):
      
      @click.command('bash-complete')
      @click.pass_context
      def bash_complete(ctx):
          """Display the commands to set up bash completion.
          """
          bash_name = _bash_complete_name(app_name)
          click.echo("""
  eval "`_{bash_name}_COMPLETE=source {app_name}`"
  # Run this command to configure your shell:
  # eval `{command}`
  """.format(
              bash_name=bash_name,
              app_name=app_name,
              command=ctx.command_path
          ).strip())
      return bash_complete
docs: Return a command that outputs the script that the user can run
      to activate bash completion.
  
      :param str app_name: the name of the app