Empirically verify whether .pth files are supported in inst. dir

def check_pth_processing(self):
        """Empirically verify whether .pth files are supported in inst. dir"""
        instdir = self.install_dir
        log.info("Checking .pth file support in %s", instdir)
        pth_file = self.pseudo_tempname() + ".pth"
        ok_file = pth_file + '.ok'
        ok_exists = os.path.exists(ok_file)
        tmpl = _one_liner("""
            import os
            f = open({ok_file!r}, 'w')
            f.write('OK')
            f.close()
            """) + '\n'
        try:
            if ok_exists:
                os.unlink(ok_file)
            dirname = os.path.dirname(ok_file)
            pkg_resources.py31compat.makedirs(dirname, exist_ok=True)
            f = open(pth_file, 'w')
        except (OSError, IOError):
            self.cant_write_to_target()
        else:
            try:
                f.write(tmpl.format(**locals()))
                f.close()
                f = None
                executable = sys.executable
                if os.name == 'nt':
                    dirname, basename = os.path.split(executable)
                    alt = os.path.join(dirname, 'pythonw.exe')
                    use_alt = (
                        basename.lower() == 'python.exe' and
                        os.path.exists(alt)
                    )
                    if use_alt:
                        # use pythonw.exe to avoid opening a console window
                        executable = alt

                from distutils.spawn import spawn

                spawn([executable, '-E', '-c', 'pass'], 0)

                if os.path.exists(ok_file):
                    log.info(
                        "TEST PASSED: %s appears to support .pth files",
                        instdir
                    )
                    return True
            finally:
                if f:
                    f.close()
                if os.path.exists(ok_file):
                    os.unlink(ok_file)
                if os.path.exists(pth_file):
                    os.unlink(pth_file)
        if not self.multi_version:
            log.warn("TEST FAILED: %s does NOT support .pth files", instdir)
        return False