Protection agains null
@@ -72,7 +72,7 @@ def comparable_version(version_string, repo_type=None):
highest_versions = []
if repo_type:
backend = backend_cls.get(repo_type)
- if backend.fallback_branch:
+ if backend and backend.fallback_branch:
highest_versions.append(backend.fallback_branch)
highest_versions.extend([LATEST_VERBOSE_NAME, STABLE_VERBOSE_NAME])
