How to delete a network analysis dataset via a script?

[CassKalinski]

I am trying to delete the network analysis dataset as part of a workflow, but having no success. Is there an arcpy protocol that can be used to delete the dataset and feature classes? I have attempted to use the arcpy.Delete_management() call with no success.

Did see this in the Data Management - Delete documentation...
'Feature classes and tables participating in a network analysis dataset or a topology cannot be deleted'

But I can manually delete them from the GDB after I am done with them. But not with a script?

# General workflow...
na_lyr_name = "Service Area"
na_result = arcpy.na.MakeServiceAreaAnalysisLayer(routing_src, na_lyr_name, etc)
arcpy.na.AddLocations(na_lyr_name, etc)
arcpy.na.Solve(na_lyr_name, "SKIP", "TERMINATE", None, '')
na_lyr = na_result[0]

# Go create feature layers off the lines and polygon results of the network analysis...
# Then clean up the now unneeded NA dataset...

# First tried just deleting the dataset itself...
arcpy.Delete_management(na_lyr)
# or...
arcpy.Delete_management(na_lyr_name) 

# Then tried looping through the layers
for lyr in na_lyr.listLayers():
    layer_path = os.path.join(DATA_GDB, lyr.name)    
    temp = arcpy.Delete_management(layer_path)
    # debug...returns True and layer name
    print(temp, lyr.name)

No errors thrown. The 'temp' print statement in there shows the Delete reporting successful. But the dataset remains in the GDB when I examine the file. 

Context:

This is a workflow that will be repeated quarterly, maybe monthly. The process is pretty standard: build a network along roadways from fixed points to create a service area. Then buffers are then built off the service area and passed on to a web map and web app.

I could just have someone manually go in after every run to delete the NA layers but would prefer the script clean up after itself. 

[DanPatterson]

Have you tried deleting what may exist from a previous run first at the start of your script?

In other words if it "exists" delete it, then proceed on from there. (move your delete management line to the top)

[CassKalinski]

Will give that a try...

[CassKalinski · Accepted solution]

Moving the code I had before to the front did not work, but that lead me to another solution. Running this at the start of the script works...

dataSets = arcpy.ListDatasets("ServiceArea*", "All")
if dataSets:
    arcpy.AddMessage('Deleting prior datasets...')
    for d in dataSets:
        print(d)
        arcpy.Delete_management(d)
    arcpy.AddMessage('\tPrior service area datasets deleted')
else:
    arcpy.AddMessage('No prior service area datasets found')

Network Analysis names all the datasets 'ServiceArea###', with that last piece being some kind of hash value. Can key off that to build the list to delete. Interestingly, using arcpy.ListDatasets("*", "Network") does not pick up the datasets.

Thank you Dan for the nudge in a working direction!