def _merge_parts(list_de_tuple_parts_id):
    """ Merge two consecutives strings with the same tag """
    if len(list_de_tuple_parts_id) <= 1:
        return list_de_tuple_parts_id
    i = 0
    j = 1
    sentences, tags = zip(*list_de_tuple_parts_id)
    tags = list(tags)
    sentences = list(sentences)
    while j < len(list_de_tuple_parts_id):
        if tags[i] == tags[j]:
            sentences[i] = ' '.join((sentences[i], sentences[j]))
            j += 1
        else:
            i += 1
            tags[i] = tags[j]
            sentences[i] = sentences[j]
            j += 1
    list_de_tuples_merged = list(zip(sentences[:i + 1], tags[:i + 1]))
    return list_de_tuples_merged
