@stringArgs
@noKwargs
def func_is_variable(self, node, args, kwargs):
    if (len(args) != 1):
        raise InvalidCode('Is_variable takes two arguments.')
    varname = args[0]
    return (varname in self.variables)
@stringArgs
@noKwargs
def func_is_variable(self, node, args, kwargs):
    if (len(args) != 1):
        raise InvalidCode('Is_variable takes two arguments.')
    varname = args[0]
    return (varname in self.variables)