def experiment_features(
        train_reader=data_readers.toy, 
        assess_reader=None, 
        train_size=0.7,
        phi_list=[fe.manual_content_flags], 
        class_func=lt.identity_class_func,
        train_func=training.fit_logistic_at_with_crossvalidation,
        score_func=scipy.stats.stats.pearsonr,
        verbose=True):
    """Generic experimental framework for hand-crafted features. 
    Either assesses with a random train/test split of `train_reader` 
    or with `assess_reader` if it is given.