python unittest TypeError: addTest()

Question

mathfunc.py

#加法，返回a+b的值
def add(a,b):

    return a+b

# 减法，返回a-b的值
def minus(a,b):
    return a-b

# 乘法，返回a*b的值
def multi(a,b):
    return a*b

# 除法，返回a/b的值
def divide(a,b):
    return a/b

testmathfunc.py

import unittest
from mathfunc  import *


class TestMathFunc(unittest.TestCase ) :
    def test_add(self):
        self.assertEqual(3,add(1,2))
        self.assertNotEqual(3,add(2,2))

    def test_minus(self):
        self.assertEqual(1,minus(3,2))

    def test_multi(self):
        self.assertEqual(6,multi(2,3))

    def test_divide(self):
        self.assertEqual(2,divide(6,3))
        self.assertEqual(2.5,divide(5,2))

test_suit.py

import unittest

from test_mathfunc import *

if __name__ =="__main__":
    suite =unittest.TestSuite
    t =    TestMathFunc("test_multi")
    print(t)
    suite.addTest(TestMathFunc("test_multi"))


    #tests= [TestMathFunc("test_add"),TestMathFunc("test_divide"),TestMathFunc("test_minus")]

    #suite.addTests(tests)
#    runner = unittest.TextTestRunner(verbosity=2)
#    runner.run(suite)

suite.addTest(TestMathFunc("test_multi")) 报错
TypeError: addTest() missing 1 required positional argument: 'test'

为什么
我看别人的 博客都这么写的