python函数定义中形参特殊用法，形参前的星号是什么意思？

_tuple = (1,)
_dict = {'name': '苏南大叔', 'age': 18}
print(_tuple,type(_tuple))
print(_dict,type(_dict))

(1,) <class 'tuple'>
{'name': '苏南大叔', 'age': 18} <class 'dict'>

def test(a1,*args,**kwargs):
    print(args,args[0],type(args))
    print(kwargs,kwargs["a2"],type(kwargs))
test("a","b","c",a2="a2")

('b', 'c') b <class 'tuple'>
{'a2': 'a2'} a2 <class 'dict'>

def test(a, b, *c):
    print(c, type(c))      # ("大","叔") <class 'tuple'>
test("苏", "南", "大", "叔")

def test(a, b, *c, d):
    print(c, type(c))
test("苏", "南", "大", "叔", d="博客")  # ('大', '叔') <class 'tuple'>

test("苏", "南", "大", "叔", "博客")    # test() missing 1 required keyword-only argument: 'd'

def test(a, b, **c):
    print(c, type(c))
test("苏", "南", "大", "叔")  # TypeError: test() takes 2 positional arguments but 4 were given
test("苏", "南", "叔")  # TypeError: test() takes 2 positional arguments but 3 were given

def test(a, b, **c, d): # SyntaxError: arguments cannot follow var-keyword argument
    print(c, type(c))

def test(a, b, **c):
    print(c, type(c)) 
test("苏", "南", c="大", d="叔")   #  {'c': '大', 'd': '叔'} <class 'dict'>

def test(a, b, c="默认值", *d, e, **f):
    print(c, type(c))
    print(d, type(d))
    print(e, type(e))
    print(f, type(f))

test("苏", "南", d="大", e="叔", f="博客")

默认值 <class 'str'>
() <class 'tuple'>
叔 <class 'str'>
{'d': '大', 'f': '博客'} <class 'dict'>