Describes the cause and action for error messages.
Error Message(English)：
3 has does not support reduce() function
Python generators and reduce
https://stackoverflow.com/questions/41455475/python-generators-and-reduce
NameError: name 'reduce' is not defined in Python
https://stackoverflow.com/questions/8689184/nameerror-name-reduce-is-not-defined-in-python
Reduce function with three parameters
https://stackoverflow.com/questions/19589233/reduce-function-with-three-parameters
What is the problem with reduce()?
https://stackoverflow.com/questions/181543/what-is-the-problem-with-reduce
reduce() in Python - GeeksforGeeks
https://www.geeksforgeeks.org/reduce-in-python/
Python reduce() function - The Python Guru
https://thepythonguru.com/python-builtin-functions/reduce/
Python Tutorial: Lambda Operator, filter, reduce and map
https://www.python-course.eu/python3_lambda.php
Built-In Function Changes ? Conservative Python 3 Porting Guide 1.0 ...
https://portingguide.readthedocs.io/en/latest/builtins.html
2to3を使ってコードをPython 3に移植する - Dive Into Python 3 日本語版
http://diveintopython3-ja.rdy.jp/porting-code-to-python-3-with-2to3.html