'string', 'ad_study_end_time' => 'datetime', 'ad_study_id' => 'string', 'ad_study_name' => 'string', 'ad_study_start_time' => 'datetime', 'cell_id' => 'string', 'cell_name' => 'string', 'holdout_size' => 'float', 'ico_type' => 'string', 'objectives' => 'list