local variable '_partition_vbmeta' referenced before assignment

Traceback in matrix reported by user

Traceback (most recent call last):
  File "/home/satcom886/apps/pmbootstrap/pmb/__init__.py", line 49, in main
    getattr(frontend, args.action)(args)
  File "/home/satcom886/apps/pmbootstrap/pmb/helpers/frontend.py", line 186, in install
    pmb.install.install(args)
  File "/home/satcom886/apps/pmbootstrap/pmb/install/_install.py", line 545, in install
    install_recovery_zip(args)
  File "/home/satcom886/apps/pmbootstrap/pmb/install/_install.py", line 476, in install_recovery_zip
    pmb.install.recovery.create_zip(args, suffix)
  File "/home/satcom886/apps/pmbootstrap/pmb/install/recovery.py", line 18, in create_zip
    vars = pmb.flasher.variables(args, flavor, method)
  File "/home/satcom886/apps/pmbootstrap/pmb/flasher/variables.py", line 36, in variables
    "$PARTITION_VBMETA": _partition_vbmeta,
UnboundLocalError: local variable '_partition_vbmeta' referenced before assignment