@classmethod
def detect(cls, old_config, new_config):
    """Detect if commit hash in `new_config` differs from `old_config`"""
    old_hash_commit = old_config['metadata'].get('VCS', None)
    new_hash_commit = new_config['metadata'].get('VCS')
    if old_hash_commit is None or old_hash_commit != new_hash_commit:
        yield cls(old_config, new_config)
