'Collects any information that\'s necessary to execute this
transformer\'s transform method.'

@classmethod
def collect(cls, block_structure):

    block_structure.request_xblock_fields(*cls.FIELDS_TO_COLLECT)
    cls._collect_max_scores(block_structure)
    collect_unioned_set_field(block_structure=block_structure, transformer=cls, merged_field_name='subsections', filter_by=(lambda block_key: (block_key.block_type == 'sequential')))
    cls._collect_explicit_graded(block_structure)
    cls._collect_grading_policy_hash(block_structure)
