def generate_speech_segments(corpus):
    """
    create a generateor of (subset, segment)-tuples from a corpus whereas subset is either train|dev|test and segment
    is a speech segment that does not contain numbers in its transcrupt
    :param corpus: a corpus
    :return: generator as specified above
    """
    return ((corpus_entry.subset, seg) for corpus_entry in corpus for seg in corpus_entry.speech_segments_not_numeric)