Workaround to silence dangling reference warning.

[hgreenlee]

Description

Workaround to silence false positive dangling reference warning. Fix suggested by Gianluca.

• Have you added a label? (bug/enhancement/physics etc.)
• Have you assigned at least 1 reviewer?
• Is this PR related to an open issue / project?
• Does this PR affect CAF data format? If so, please assign a CAF maintainer as additional reviewer. @Gianluca Petrillo and @thomas Jones
• Does this PR require merging another PR in a different repository (such as sbnanobj/sbnobj etc.)? If so, please link it in the description.
• Are you submitting this PR on behalf of someone else who made the code changes? If so, please mention them in the description.