code: def get_and_subtract(self, delta):
          '''
          Atomically subtracts `delta` from the current value and returns the
          old value.
  
          :param delta: The delta to subtract.
          '''
          with self._lock.exclusive:
              oldval = self._value
              self._value -= delta
              return oldvaf get_and_subtract(self, delta):
          '''
          Atomically subtracts `delta` from the current value and returns the
          old value.
  
          :param delta: The delta to subtract.
          '''
          with self._lock.exclusive:
              oldval = self._value
              self._value -= delta
              return oldval
docs: Atomically subtracts `delta` from the current value and returns the
          old value.
  
          :param delta: The delta to subtract.