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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def decryption(self, ciphertext, key):
 """ Builds a single cycle AES Decryption circuit :param WireVector ciphertext: data to decrypt :param WireVector key: AES key to use to encrypt (AES is symmetric) :return: a WireVector containing the plaintext """

        if len(ciphertext) != self._key_len:
            raise pyrtl.PyrtlError("Ciphertext length is invalid")
        if len(key) != self._key_len:
            raise pyrtl.PyrtlError("key length is invalid")
        key_list = self._key_gen(key)
        t = self._add_round_key(ciphertext, key_list[10])

        for round in range(1, 11):
            t = self._inv_shift_rows(t)
            t = self._sub_bytes(t, True)
            t = self._add_round_key(t, key_list[10 - round])
            if round != 10:
                t = self._mix_columns(t, True)

        return t