def _check_header(self, header_name):
        """
        Check if the given header can be included by trying to compile a file
        that contains only an #include line.
        """
        self.compiler.announce("checking for {} ...".format(header_name), 0)
        return self._compile_helper("#include <{}>\n".format(header_name))

        Check if the given header can be included by trying to compile a file
        that contains only an #include line.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/_setup.py