docs: def verify_fun(lazy_obj, fun):
      '''
      Check that the function passed really exists
      '''
      if not fun:
          raise salt.exceptions.SaltInvocationError(
              'Must specify a function to run!\n'
              'ex: manage.up'
          )
      if fun not in lazy_obj:
          # If the requested function isn't available, lets say why
          raise salt.exceptions.CommandExecutionError(lazy_obj.missing_fun_string(fun))