Again, what are you trying to do?  If you're trying to save a call to g_charsetConverter, notice that this is called once at the start of a python script, which is potentially loading a python DLL, parsing a bunch of code out of a text file (or a bunch of text files) compiling that code into the .pyc and so on.

i.e. the trivial conversion of a path to utf8 is just that: trivial.