'Collect the `max_score` for every block in the provided `block_structure`.'

@classmethod
def _collect_max_scores(cls, block_structure):

    for block_locator in block_structure.post_order_traversal():
        block = block_structure.get_xblock(block_locator)
        if getattr(block, 'has_score', False):
            cls._collect_max_score(block_structure, block)
