'Updates the application version to have the properties.
:type application_name: string
:param application_name: The name of the application associated with
this version.  If no application is found with this name,
UpdateApplication returns an InvalidParameterValue error.
:type version_label: string
:param version_label: The name of the version to update. If no
application version is found with this label, UpdateApplication
returns an InvalidParameterValue error.
:type description: string
:param description: A new description for this release.'

def update_application_version(self, application_name, version_label, description=None):

    params = {'ApplicationName': application_name, 'VersionLabel': version_label}
    if description:
        params['Description'] = description
    return self._get_response('UpdateApplicationVersion', params)
