Selective Metagraph & Mechagraph inconsistency

[antlerminator]

Selective Metagraph & Mechagraph has an issue where it'll return 0 instead of null for the netuid field if the netuid index is not passed as an argument. This is inconsistent with how other selective indexes behave when they are absent.

In above screenshot, the netuid field is 0 instead of being null.

[open-junius]

You are right. it is different with other field. I have a question, since the netuid is a mandatory input, should we always set netuid even its index not in the list. @antlerminator