def METHOD_NAME(expand: Optional[pulumi.Input[Optional[str]]] = None,
                            resource_group_name: Optional[pulumi.Input[str]] = None,
                            route_filter_name: Optional[pulumi.Input[str]] = None,
                            opts: Optional[pulumi.InvokeOptions] = None) -> pulumi.Output[GetRouteFilterResult]:
    """
    Gets the specified route filter.
    :param str expand: Expands referenced express route bgp peering resources.
    :param str resource_group_name: The name of the resource group.
    :param str route_filter_name: The name of the route filter.
    """
    ...