def pk_decrypt(encrypted, private_key):
    """
    Return `encrypted` decrypted by `private_key` as a string.

    encrypted: list
        Chunks of encrypted data returned by :func:`pk_encrypt`.

    private_key: :class:`Crypto.PublicKey.RSA`
        Private portion of key pair.
    """
    data = ''
    for chunk in encrypted:
        data += private_key.decrypt(chunk)
    return data