def METHOD_NAME(
        self, resource_group_name, virtual_wan_name, custom_headers=None, raw=False, polling=True, **operation_config):
    """Gives the list of VpnServerConfigurations associated with Virtual Wan
    in a resource group.
    :param resource_group_name: The resource group name.
    :type resource_group_name: str
    :param virtual_wan_name: The name of the VirtualWAN whose associated
     VpnServerConfigurations is needed.
    :type virtual_wan_name: str
    :param dict custom_headers: headers that will be added to the request
    :param bool raw: The poller return type is ClientRawResponse, the
     direct response alongside the deserialized response
    :param polling: True for ARMPolling, False for no polling, or a
     polling object for personal polling strategy
    :return: An instance of LROPoller that returns
     VpnServerConfigurationsResponse or
     ClientRawResponse<VpnServerConfigurationsResponse> if raw==True
    :rtype:
     ~msrestazure.azure_operation.AzureOperationPoller[~azure.mgmt.network.v2019_11_01.models.VpnServerConfigurationsResponse]
     or
     ~msrestazure.azure_operation.AzureOperationPoller[~msrest.pipeline.ClientRawResponse[~azure.mgmt.network.v2019_11_01.models.VpnServerConfigurationsResponse]]
    :raises: :class:`CloudError<msrestazure.azure_exceptions.CloudError>`
    """
    raw_result = self._list_initial(
        resource_group_name=resource_group_name,
        virtual_wan_name=virtual_wan_name,
        custom_headers=custom_headers,
        raw=True,
        **operation_config
    )
    def get_long_running_output(response):
        deserialized = self._deserialize('VpnServerConfigurationsResponse', response)
        if raw:
            client_raw_response = ClientRawResponse(deserialized, response)
            return client_raw_response
        return deserialized
    lro_delay = operation_config.get(
        'long_running_operation_timeout',
        self.config.long_running_operation_timeout)
    if polling is True: polling_method = ARMPolling(lro_delay, lro_options={'final-state-via': 'location'}, **operation_config)
    elif polling is False: polling_method = NoPolling()
    else: polling_method = polling
    return LROPoller(self._client, raw_result, get_long_running_output, polling_method)