charmap' codec can't decode byte 0x9d in position 92: character maps to <undefined> code example

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

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

Example 2: return codecs.charmap_decode(input,self.errors,decoding_table)[0] UnicodeDecodeError: 'charmap' codec can't decode byte 0x8d in position 280: character maps to

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