Returns a list of distributed virtual switches (DVSs).
    The list can be filtered by the datacenter or DVS names.

    datacenter
        The datacenter to look for DVSs in.
        Default value is None.

    dvs_names
        List of DVS names to look for. If None, all DVSs are returned.
        Default value is None.

    .. code-block:: bash

        salt '*' vsphere.list_dvss

        salt '*' vsphere.list_dvss dvs_names=[dvs1,dvs2]

def list_dvss(datacenter=None, dvs_names=None, service_instance=None):
    '''
    Returns a list of distributed virtual switches (DVSs).
    The list can be filtered by the datacenter or DVS names.

    datacenter
        The datacenter to look for DVSs in.
        Default value is None.

    dvs_names
        List of DVS names to look for. If None, all DVSs are returned.
        Default value is None.

    .. code-block:: bash

        salt '*' vsphere.list_dvss

        salt '*' vsphere.list_dvss dvs_names=[dvs1,dvs2]
    '''
    ret_list = []
    proxy_type = get_proxy_type()
    if proxy_type == 'esxdatacenter':
        datacenter = __salt__['esxdatacenter.get_details']()['datacenter']
        dc_ref = _get_proxy_target(service_instance)
    elif proxy_type == 'esxcluster':
        datacenter = __salt__['esxcluster.get_details']()['datacenter']
        dc_ref = salt.utils.vmware.get_datacenter(service_instance, datacenter)

    for dvs in salt.utils.vmware.get_dvss(dc_ref, dvs_names, (not dvs_names)):
        dvs_dict = {}
        # XXX: Because of how VMware did DVS object inheritance we can\'t
        # be more restrictive when retrieving the dvs config, we have to
        # retrieve the entire object
        props = salt.utils.vmware.get_properties_of_managed_object(
            dvs, ['name', 'config', 'capability', 'networkResourcePool'])
        dvs_dict = _get_dvs_config_dict(props['name'], props['config'])
        # Product info
        dvs_dict.update(
            {'product_info':
             _get_dvs_product_info(props['name'],
                                   props['config'].productInfo)})
        # Link Discovery Protocol
        if props['config'].linkDiscoveryProtocolConfig:
            dvs_dict.update(
                {'link_discovery_protocol':
                 _get_dvs_link_discovery_protocol(
                     props['name'],
                     props['config'].linkDiscoveryProtocolConfig)})
        # Capability
        dvs_dict.update({'capability':
                         _get_dvs_capability(props['name'],
                                             props['capability'])})
        # InfrastructureTrafficResourceConfig - available with vSphere 6.0
        if hasattr(props['config'], 'infrastructureTrafficResourceConfig'):
            dvs_dict.update({
                'infrastructure_traffic_resource_pools':
                _get_dvs_infrastructure_traffic_resources(
                    props['name'],
                    props['config'].infrastructureTrafficResourceConfig)})
        ret_list.append(dvs_dict)
    return ret_list