Hi Stephen,
welcome to the community!
I ran into similar problems some weeks ago and I think the solution is the following:
If you have the possibility to go to the Neo4j Browser in between sending queries from python, you can simply change the database against which you want to do the query by the "use" command:
:use targetDatabase
If you do not have the possibility (I do not have it, either) but want to switch databases from your code, I guess the answer for now is that it is not possible since the 4.0 Python drivers are not out yet.
In this forum entry (Cannot create multiple databases through python client(Neo4j 4.0) - #5 by andrew_bowman) it is announced that the driver is expected to be released in Q2.
Regards,
Elena