Uncaught Error: UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 690: character maps to code example

Example 1: 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")

Example 2: UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 92: character maps to

file = open(filename, encoding="cp437")