Standardize import.

Every other file uses this pattern.

examples/run_ner.py

@@ -25,7 +25,6 @@ import random
 import numpy as np
 import torch
 from seqeval.metrics import f1_score, precision_score, recall_score
-from tensorboardX import SummaryWriter
 from torch.nn import CrossEntropyLoss
 from torch.utils.data import DataLoader, RandomSampler, SequentialSampler, TensorDataset
 from torch.utils.data.distributed import DistributedSampler
@@ -54,6 +53,12 @@ from transformers import (
 from utils_ner import convert_examples_to_features, get_labels, read_examples_from_file
 
 
+try:
+    from torch.utils.tensorboard import SummaryWriter
+except ImportError:
+    from tensorboardX import SummaryWriter
+
+
 logger = logging.getLogger(__name__)
 
 ALL_MODELS = sum(