PyAnalysisCore: Fix clang 10 warning.

Fix use of dangling iterators.

This merge request affects 1 package:

• PhysicsAnalysis/PyAnalysis/PyAnalysisCore

added Analysis master review-pending-level-1 labels

CI Result FAILURE (hash c04b1c7c)

	Athena	AthSimulation	AnalysisBase	AthGeneration
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 17400]

The changes are fine and the CI issues are unrelated. Approving.

Jason (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit f3df4dad

added sweep:ignore label