'Returns all units names, their urls and validation messages.
Returns:
{\'user_partition_id\':
\'label\': \'Unit 1 / Experiment 1\',
\'url\': \'url_to_unit_1\',
\'validation\': {\'message\': \'a validation message\', \'type\': \'warning\'}
\'label\': \'Unit 2 / Experiment 2\',
\'url\': \'url_to_unit_2\',
\'validation\': {\'message\': \'another validation message\', \'type\': \'error\'}'

@staticmethod
def _get_content_experiment_usage_info(store, course, split_tests):

    usage_info = {}
    for split_test in split_tests:
        if (split_test.user_partition_id not in usage_info):
            usage_info[split_test.user_partition_id] = []
        unit = split_test.get_parent()
        if (not unit):
            log.warning('Unable    to    find    parent    for    split_test    %s', split_test.location)
            continue
        usage_info = GroupConfiguration._get_usage_info(course=course, unit=unit, item=split_test, usage_info=usage_info, group_id=split_test.user_partition_id, scheme_name=RANDOM_SCHEME)
    return usage_info
