Let domain.get_user return empty dict ({}) instead of None when not found

[twd2]

Let domain.get_user return empty dict ({}) instead of None when not found.

[moesoha]

This will make some codes simpler

[breezewish]

Why would it make code simpler?

[ZsgsDesign]

In our projects, we would do that.

In general, processing data with the same return type is easier, you wouldn't like the idea that some method sometimes returns a certain type and on the other times another. Likewise, unify data types by making None to {} is a lot easier for programming and a bit more understandable.