fix some issues in pr

hivemind/optim/__init__.py

@@ -1,5 +1,5 @@
 from hivemind.optim.base import DecentralizedOptimizerBase
 from hivemind.optim.collaborative import CollaborativeOptimizer
 from hivemind.optim.performance_ema import PerformanceEMA
-from hivemind.optim.decentralized_optimizers import DecentralizedOptimizer, DecentralizedSGD, DecentralizedAdam
+from hivemind.optim.averaged import DecentralizedOptimizer, DecentralizedSGD, DecentralizedAdam
 from hivemind.optim.adaptive import CollaborativeAdaptiveOptimizer