How to parse NETWORK_LAYERS results in Python?

[LaurieMhu]

I would like to use Trace with result_types=['NETWORK_LAYERS']. I am unable to drill the layers in out_network_layer.

Here is an example of an attempt:

out_netk_layer = "out_net_lay"
stream_layer_name = 'Stream'
res = arcpy.tn.Trace(in_trace_network=t_network,
			trace_type="SHORTEST_PATH",
			starting_points=starting_points,
			shortest_path_network_attribute_name="Shape length",
			validate_consistency="VALIDATE_CONSISTENCY",
			result_types=['NETWORK_LAYERS'],
			out_network_layer=out_netk_layer)
	
if res:
	total_length = 0
	feature_class_path = '{}\\{}'.format(out_netk_layer, stream_layer_name)
    with arcpy.da.SearchCursor(feature_class_path, ["SHAPE@"]) as cursor:
        for row in cursor:
            shape = row[0]
            if shape.isSelected:
				total_length += shape.length
	arcpy.AddMessage("Total length : {} meters".format(total_length))
else:
	arcpy.AddWarning("no trace result")

arcgisscripting.ExecuteError: Execution failed. The parameters are not valid.

ERROR 000732: Input Entities: Dataset out_net_lay/stream does not exist or is not supported

Where can I find a code example? What anomaly do you see here? Thanks for everything

[Dan_Joyce_OE]

I'm encountering the same issue.  I'm expecting the trace to return a Group Layer object that could then be manipulated in the same way that the old Geometric Network trace results could be processed.  It appears the new trace only returns a string when the result type = 'NETWORK_LAYERS'.

trace_result = arcpy.tn.Trace(network, 'CONNECTED', start_points, lyr_valve, include_barriers='INCLUDE_BARRIERS', validate_consistency='VALIDATE_CONSISTENCY', result_types='NETWORK_LAYERS', out_network_layer='TRACE1')

print(trace_result)

> Trace_Results_Aggregated_Points

It's frustrating because the script works as intended within ArcGIS Pro but doesn't as a stand-alone.  I suspect that the Network Layer result type is only valid within ArcGIS Pro.  The wording in the documentation should be made more clear if this is the case.

Dan_Joyce_OE_0-1702970343645.png

At the moment, this isn't a useful option for me as the stand-alone script gets published as a GP service so that it can be called from a web app.