Error when building with Custom Rustc wrapper built on Python

Hi Everyone,

I am working on a fuzzer for Rust and I am trying to build the binary with sanitizers and I am currently stuck because my current rustc.py which is a wrapper I built. However, when I build using cargo and the RUSTC_WRAPPER=./rustc.py, I encountered an error on the cfg that goes like this:

error: failed to parse the cfg from rustc --print=cfg
lib___.rlib
lib___.so
...
Caused by:
failed to parse as a cfg expression: expected identifier, but cfg expression ended

Anyone encountered this issue before?