python函数中，双星号**的作用

https://www.geeksforgeeks.org/packing-and-unpacking-arguments-in-python/ 

https://blog.csdn.net/xiaoqu001/article/details/78823498

** is used for dictionaries

# A sample program to demonstrate unpacking of # dictionary items using ** def fun(a, b, c):     print(a, b, c) # A call with unpacking of dictionary d = {'a':2, 'b':4, 'c':10} fun(**d)