'Gets the supported ontapi version.'

def get_ontapi_version(self, cached=True):

    if cached:
        return self.connection.get_api_version()
    ontapi_version = netapp_api.NaElement('system-get-ontapi-version')
    res = self.connection.invoke_successfully(ontapi_version, False)
    major = res.get_child_content('major-version')
    minor = res.get_child_content('minor-version')
    return (major, minor)
