code: def encipher_shift(plaintext, plain_vocab, shift):
    
    ciphertext = []
    cipher = ShiftEncryptionLayer(plain_vocab, shift)
  
    for _, sentence in enumerate(plaintext):
      cipher_sentence = []
      for _, character in enumerate(sentence):
        encrypted_char = cipher.encrypt_character(character)
        cipher_sentence.append(encrypted_char)
      ciphertext.append(cipher_sentence)
  
    return ciphertext
docs: Encrypt plain text with a single shift layer.
  
    Args:
      plaintext (list of list of Strings): a list of plain text to encrypt.
      plain_vocab (list of Integer): unique vocabularies being used.
      shift (Integer): number of shift, shift to the right if shift is positive.
    Returns:
      ciphertext (list of Strings): encrypted plain text.