def parse(self, filename, constraint):
        # type: (str, bool) -> Iterator[ParsedLine]
        """Parse a given file, yielding parsed lines.
        """
        for line in self._parse_and_recurse(filename, constraint):
            yield line
Parse a given file, yielding parsed lines.
        
product/gradle-plugin/src/main/python/pip/_internal/req/req_file.py