怎么获得unittest返回值，也就是代码中的 return str

#-*- coding: UTF-8 -*-
from threading import Timer
import time
from selenium import webdriver
from nose_parameterized import parameterized
import unittest

class TestAdd(unittest.TestCase):
    def setUp(self):
        self.driver=webdriver.Chrome()
        self.driver.maximize_window()
        self.driver.get("http://www.juxiangyou.com")
    @parameterized.expand([
         ('syt350964652@QQ.com'),
         ('syt350964653@QQ.com'),
    ])
    def test_add(self,username):
             driver=self.driver
       driver.find_element_by_id('account').send_keys(username)
       time.sleep(5)
       driver.find_element_by_id('password').send_keys('111')
       time.sleep(11)
       driver.find_element_by_link_text('登 录').click()
       time.sleep(2)
       dqjb=self.driver.current_window_handle
       driver.find_element_by_link_text('匠神部落').click()
       time.sleep(2)
       list_jb=self.driver.window_handles
       for jb in list_jb:
           if jb!=dqjb:
               jb_two=jb
       driver.switch_to.window(jb_two)
       driver.find_element_by_id('forgeHall').click()
       time.sleep(2)
       time_num=self.driver.find_element_by_class_name('forge').text
       print(time_num[-8:])
       str=time_num[-8:]
       return str
    def tearDown(self):
        self.driver.quit()
if __name__=='__main__':
    unittest.main()

https://blog.csdn.net/qq_39314932/article/details/83051973

这个 ‘a’ 不传会 报错， 有什么解决办法吗？

#coding=utf-8
import unittest

class AlienTest1(unittest.TestCase):
    def test_1_run(self):
        print("hello world_1")
        str = "123"
        return str
if __name__ == '__main__':
    str=AlienTest1.test_1_run('a')
    print(str)
    suite1 = unittest.makeSuite(AlienTest1)
    unittest.TextTestRunner().run(suite1)