+ :param decrypt_policy: If the message contains any encrypted
+ parts, and decrypt_policy is set to
+ :attr:`DECRYPTION_POLICY`.TRUE, notmuch will try to
+ decrypt the message and index the cleartext, stashing any
+ discovered session keys. If it is set to
+ :attr:`DECRYPTION_POLICY`.FALSE, it will never try to
+ decrypt during indexing. If it is set to
+ :attr:`DECRYPTION_POLICY`.AUTO, then it will try to use
+ any stashed session keys it knows about, but will not try
+ to access the user's secret keys.
+ :attr:`DECRYPTION_POLICY`.NOSTASH behaves the same as
+ :attr:`DECRYPTION_POLICY`.TRUE except that no session keys
+ are stashed in the database. If decrypt_policy is set to
+ None (the default), then the database itself will decide
+ whether to decrypt, based on the `index.decrypt`
+ configuration setting (see notmuch-config(1)).
+