global_route_debug error

[Pxx-X]

I use ORFS to run a flow of one benchmark with command make DESIGN_CONFIG=./path/config.mk, and I get "4_cts.odb".
Then I run openroad and input the command:

1. read_db 4_cts.odb
2. global_route_debug -st

openroad return can't read "keys(-net)": no such variable, I don't know why, is it a bug or I made some mistake?
The Document indicate that I should input global_route_debug before global_route. And I try both(befor and after global_route, the result are the same)
The .odb file is here
Thank you very much!

[Pxx-X]

I fixed this problem. I made a mistake, I should run in debug mode, not just run the openroad with debug flag.