You are working on the ga4gh/vrs-python repository. The source code is checked out at /testbed at commit…

You are working on the ga4gh/vrs-python repository. The source code is checked out at /testbed at commit…: a task in SWE-Lego-RL-2699 (Harbor dataset). This is because the hgvs tools.extract allele values can return None when the description is not HGVS syntax. And there is no null defense in…

The task

This is because the `hgvs_tools.extract_allele_values` can return `None` when the description is not HGVS syntax. And there is no null defense in `AlleleTranslator._create_allele`.

Part of Lego-X/Lego-RL-2699.