REF: improved code for label removal
REF: improved code for label removal

Former-commit-id: 75bab3ac325e5d4a3582123d0f8617f6d6344aa8 [formerly 9cd0d753651f966934d7ae467f046a78f761242e]
Former-commit-id: 127c466667b8617541850f99a48625654daaa738
Former-commit-id: 706c7e16374f1d62cdd94d479b28452129bc376f
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox