def convert_text(texts, alphabet):
    lens = list(map(len, texts))
    lens = np.array(lens)
    max_len = np.max(lens)
    true_masks = np.zeros((len(texts), max_len), dtype=np.int32)
    for i, text in enumerate(texts):
        k = 0
        for char in (text):
            if char not in alphabet:
                pass
                #print("bad char: `{}`".format(char))
                # assert(False)
                #true_masks[i, k] = 2
            else:
                true_masks[i, k] = alphabet.index(char) + 1
                k += 1
        lens[i]=k
    return true_masks, lens