def decrypt_AES(cipher, package, iv):
    """
    Decrypts an AES package using a specific cipher and iv
    :param cipher: String. Key for decryption.
    :param package: String. The base64 encoded data to be decrypted.
    :param iv: String. 16 characters. Used to randomize the data for repeated
        cipher usage by changing this value. Can be sent plaintext.
    """
    from Crypto.Cipher import AES
    from base64 import b64decode
    cipher_obj = AES.new(cipher, AES.MODE_CBC, iv)
    return cipher_obj.decrypt(b64decode(package))
