adding tests to examples - updating summary module - coverage update

pytorch_transformers/modeling_bert.py

@@ -28,7 +28,6 @@ import torch
 from torch import nn
 from torch.nn import CrossEntropyLoss, MSELoss
 
-from .file_utils import cached_path
 from .modeling_utils import WEIGHTS_NAME, CONFIG_NAME, PretrainedConfig, PreTrainedModel, prune_linear_layer
 
 logger = logging.getLogger(__name__)