'Sets item secret to `secret`. If `content_type` is given,
also sets the content type of the secret (``text/plain`` by
default).'

def set_secret(self, secret, content_type='text/plain'):

    self.ensure_not_locked()
    if (not self.session):
        self.session = open_session(self.bus)
    secret = format_secret(self.session, secret, content_type)
    self.item_iface.SetSecret(secret, signature='(oayays)')
