I may be misunderstanding, but it sounds like = is not acceptable in the final result, so it's not enough to remove only 2 of 4 ='s. You want to make sure nothing messed up your string. So if the code existed, what you'd want is:

```
assert salt.count("=") <= 2
salt = salt.rstrip("=", "")
assert "=" not in salt
```

I think the code I'd want, if the new parameter existed, would be:

salt = salt.rstrip("=", maxstrip=2)
assert not salt.endswith("=")

That feels *slightly* better than your version.  This version would allow there to be '=' in the middle of the string (albeit, such would not be base64, but some other kind of thing).  Obviously, I've managed to program Python without this switch for 20+ years.  But I think I'd use it occasionally.

Currently, I'd probably program my intention like this.  Let's assume this is something where the '=' is allowed in the middle.

if salt.endswith("=="):
    salt = salt[-2:]
elif salt.endswith("="):
    salt = salt[-1:]
assert not salt.endswith("=")

The version you suggested, as mentioned, would not handle a format where '=' was permitted in the middle.

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