So is there ever a good place to use mutable defaults? Yes! Mutable defaults can be very useful for caching and/or recursive algorithms:
def fibonacci(n, cache={0:0, 1:1}):
if n in cache:
return cache[n]
else:
value = fibonacci(n-1) + fibonacci(n-2)
cache[n] = value
return value
标签：return,Python,cache,value,fibonacci,defaults From： https://www.cnblogs.com/zhangzhihui/p/17477362.html