Return a list of the VMs that are on the provider

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

    ret = {}
    items = query(action='ve')

    for item in items:
        name = item.attrib['name']
        node = show_instance(name, call='action')

        ret[name] = {
            'id': node['id'],
            'image': node['platform']['template-info']['name'],
            'state': node['state'],
        }
        if 'private-ip' in node['network']:
            ret[name]['private_ips'] = [node['network']['private-ip']]
        if 'public-ip' in node['network']:
            ret[name]['public_ips'] = [node['network']['public-ip']]

    return ret