Extract a tuple of (major,minor,patch) from a firmware instance

def semver_from_firmware(self, firmware):
        '''Extract a tuple of (major,minor,patch) from a firmware instance'''
        version = firmware.get("mav-firmware-version-major",None)
        if version is None:
            return (None,None,None)
        return (firmware["mav-firmware-version-major"],
                firmware["mav-firmware-version-minor"],
                firmware["mav-firmware-version-patch"])