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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 _get_encryption_headers(key, source=False):
 """Builds customer encryption key headers :type key: bytes :param key: 32 byte key to build request key and hash. :type source: bool :param source: If true, return headers for the "source" blob; otherwise, return headers for the "destination" blob. :rtype: dict :returns: dict of HTTP headers being sent in request. """

    if key is None:
        return {}

    key = _to_bytes(key)
    key_hash = hashlib.sha256(key).digest()
    key_hash = base64.b64encode(key_hash)
    key = base64.b64encode(key)

    if source:
        prefix = "X-Goog-Copy-Source-Encryption-"
    else:
        prefix = "X-Goog-Encryption-"

    return {
        prefix + "Algorithm": "AES256",
        prefix + "Key": _bytes_to_unicode(key),
        prefix + "Key-Sha256": _bytes_to_unicode(key_hash),
    }