Return a list of the images that are on the provider

def avail_images(call=None):
    '''
    Return a list of the images that are on the provider
    '''
    if call == 'action':
        raise SaltCloudSystemExit(
            'The avail_images function must be called with '
            '-f or --function, or with the --list-images option'
        )

    items = query(action='template')
    ret = {}
    for item in items:
        ret[item.attrib['name']] = item.attrib

    return ret