pgAdmin4 Query Error "not enough values to unpack (expected 5, got 4)"

I had the same problem on Debian Buster. I had psycopg2 installed through pip3 to solve the older problem with no returns in pgadmin on Debian.

So now i went to pgadmin config (right mouse button to pgadmin icon in tray) and deleted the custom path to python libraries. After that it works great.

I'm on Ubuntu 18.04, running pgAdmin4 4.11 in Desktop mode. As user1936789 suggested, clearing the Python Path on the Python tab of the PgAdmin 4 Configuration screen cleared up the problem for me.