The goal of what I am trying to achieve is to get a list of all feature classes in every dataset in my geodatabase.
Through following blow URL I could successfully achieve result for one dataset level. https://desktop.arcgis.com/en/arcmap/10.3/analyze/modelbuilder/integrating-model-within-a-model.htm
I added an other model with dataset iterator to loop through all datasets in my geodatabase and use previous model as a sub model.
Now, as per my understanding in ModelBuilder, for each dataset iteration, the "Output Values" list from sub model will get overwritten.
How can I append the output of the sub model "Output Values" to an other list so at the end I will have a list with all feature classes in geodatabase?
I mean something like "append" or add new records to a list from "Output Values" until dataset iterator finishes.
After having all feature classes list of my geodatabase I can then do with it any geoprocessing that may suit. For example, I can merge all polygon feature classes and erase merge result from area of interest to create a land cover polygon.