Return the encoding/codepage to use.

def _get_encoding(self):
        """Return the encoding/codepage to use."""
        enco = 'utf-8'

        #  Currently only cp1252 is allowed?
        if WIN:
            import ctypes
            codepage = to_text_string(ctypes.cdll.kernel32.GetACP())
            # import locale
            # locale.getpreferredencoding()  # Differences?
            enco = 'cp' + codepage
        return enco