def is_consistent_prediction(pred_tokens, true_tokens):
    """
    check if predicted label sequence is consistent
    with the actual label sequence.
    
    consistent means:

    - same length
    - same content(after lower-casing)
    """
    lower_case = lambda tokens: map(lambda t: t.lower(), tokens)
    
    if len(pred_tokens) == len(true_tokens):
        if lower_case(pred_tokens) == lower_case(true_tokens):
            return True
    return False