ves the one time keys that the session used from the account. Returns olm_error() on failure. If the account doesn't have any matching one time keys then olm_account_last_error() will be &quot;BAD_MESSAGE_KEY_ID&quot;.</p></dd></dl><dl><dt class="spec value" id="val-encrypt_message_type"><a href="#val-encrypt_message_type" class="anchor"></a><code><span class="keyword">val</span> encrypt_message_type : <span><a href="../Types/Session/index.html#type-t">Types.Session.t</a> Ctypes_static.ptr</span> <span>&#45