Re: Two python issues

>
(a) An error-prone "feature" is returning -1 if a substring is not found
by "find", since -1 currently refers to the last item. An example:
>
 >>> s = 'qwertyuiop'
 >>> s[s.find('r')]
'r'
 >>> s[s.find('p')]
'p'
 >>> s[s.find('a')]
'p'
 >>>
>
If "find" is unsuccessful, an error message is the only clean option.
Moreover, using index -1 for the last item is a bad choice: it should be
len(s) - 1 (no laziness!).
>

I'm not sure if this answers your objection but the note in the
documentation (https://docs.python.org/3/library/stdtypes.html#str.find)
says:

The find() method should be used only if you need to know the position of
sub.

I think the use case above is a little bit different.