Problem with the '|' character?

[Saka]

Hello all, I'm trying to use the following method to find the "|" character in the following string as a little test:

[m.start() for m in re.finditer('|', 'fjd|fhjdkal|fgdha|ads')]

Strangely it returns all of the character indexes, from 0 to 21. Why? It seems to work normally with other characters.
Even more, strangely, it still returns a similar output when there is not even a "|" in the string:

[m.start() for m in re.finditer("|", 'abc')]

Output:
[0, 1, 2, 3]

Why? And how can I fix this problem? Thanks! I really need this for my new esolang!

[buran]

| is a special character in RegEx. Escape it.
here is online tester where you can experiment with regex https://regex101.com/

[Saka]

Thanks! It works perfectly now!