Just a little nitpick but using Py_BuildValue is much better to generate PyObjects from C if you are doing more than one of them instead of populating a list and converting it to a tuple to pass to the python function.

My general rule (when doing the opposite of passing C values to python as part of an extension) is to use the dedicated function, like PyLong_FromLong, when there is a single return and Py_BuildValue (with its format string for automagic conversion) when the function returns a tuple.

Oh, and if you are checking your return values from python (you are, right?) using Py_XDECREF isn't all that good of an idea since it will mask some flawed logic. I pretty much only use it when a PyObject pointer could validly be NULL (like with an optional function argument) and I'm cleaning up right before throwing an exception. Tracking python reference counts is a whole blog post in itself since some functions steal references and others don't and if you get it wrong you can easily crash the interpreter and/or create memory leaks.