def _convert_pyx_sources_to_lang(self):
if have_pyrex():<EOL><INDENT>return<EOL><DEDENT>lang = self.language or '<STR_LIT>'<EOL>target_ext = '<STR_LIT>' if lang.lower() == '<STR_LIT>' else '<STR_LIT>'<EOL>sub = functools.partial(re.sub, '<STR_LIT>', target_ext)<EOL>self.sources = list(map(sub, self.sources))<EOL>
Replace sources with .pyx extensions to sources with the target
language extension. This mechanism allows language authors to supply
pre-converted sources but to prefer the .pyx sources.