UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 6: ordinal not in range(128) code example
Example 1: UnicodeDecodeError: 'utf-8' codec can't decode byte 0xe9 in position 2892: invalid continuation byte
As suggested by Mark Ransom, I found the right encoding for that problem.
The encoding was "ISO-8859-1", so replacing
open("u.item", encoding="utf-8")
with
open('u.item', encoding = "ISO-8859-1")
will solve the problem.
Example 2: Exception: 'ascii' codec can't decode byte 0xe2 in position 7860: ordinal not in range(128)
f = open(file_path, 'r+', encoding="utf-8")