'charmap' codec can't decode byte 0x81 in position 5402: character maps to <undefined> in csv writer in python code example

Example 1: 'charmap' codec can't decode byte 0x98 in position

file = open(filename, encoding="utf8")

Example 2: 'charmap' codec can't decode byte 0x9d in position 846: character maps to

file = open(filename, encoding="utf8")