Minor imports cleaning (#402)

* code cleaning

* drop unused imports

* optimize imports

pl_examples/basic_examples/gpu_template.py

@@ -2,12 +2,13 @@
 Runs a model on a single node across N-gpus.
 """
 import os
+from argparse import ArgumentParser
+
 import numpy as np
 import torch
 
-from argparse import ArgumentParser
-from pytorch_lightning import Trainer
 from pl_examples.basic_examples.lightning_module_template import LightningTemplateModel
+from pytorch_lightning import Trainer
 
 SEED = 2334
 torch.manual_seed(SEED)