def parseVersion(self, strversion):
        """
        Parse version strings of the form Protocol '/' Major '.' Minor. E.g.
        b'HTTP/1.1'.  Returns (protocol, major, minor).  Will raise ValueError
        on bad syntax.
        """
        try:
            proto, strnumber = strversion.split(b'/')
            major, minor = strnumber.split(b'.')
            major, minor = int(major), int(minor)
        except ValueError as e:
            raise BadResponseVersion(str(e), strversion)
        if major < 0 or minor < 0:
            raise BadResponseVersion(u"version may not be negative",
                strversion)
        return (proto, major, minor)

        Parse version strings of the form Protocol '/' Major '.' Minor. E.g.
        b'HTTP/1.1'.  Returns (protocol, major, minor).  Will raise ValueError
        on bad syntax.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/_newclient.py