def add_and_get(self, delta):
        '''
        Atomically adds `delta` to the current value.

        :param delta: The delta to add.
        '''
        with self._reference.get_lock():
            self._reference.value += delta
            return self._reference.value
def add_and_get ( self , delta ) : with self . _reference . get_lock ( ) : self . _reference . value += delta return self . _reference . value
Atomically adds `delta` to the current value.

        :param delta: The delta to add.