@staticmethod
def _parse_version(version_str):
    """Convert a version string to a float.

        >>> RFBSecurityProxy._parse_version('RFB 003.008\\n')
        0.2
        """
    maj_str = version_str[4:7]
    min_str = version_str[8:11]
    return float('%d.%d' % (int(maj_str), int(min_str)))
