Style tweaks, comming from google account

Author: vlasenkoalexey

tensorflow_io/bigquery/kernels/bigquery_lib.h

@@ -253,7 +253,7 @@ class BigQueryReaderDatasetIterator : public DatasetIterator<Dataset> {
           ((*out_tensors)[i]).scalar<string>()() =
               field.value<avro::GenericEnum>().symbol();
           break;
-        case avro::AVRO_NULL:
+        case avro::AVRO_NULL:  // Fallthrough;
           break;
         default:
           return errors::InvalidArgument("unsupported data type: ",

tensorflow_io/bigquery/python/ops/bigquery_api.py

@@ -28,7 +28,7 @@
 from __future__ import print_function
 
 import collections
-import operator
+from operator import itemgetter
 
 from tensorflow.python.data.experimental.ops import interleave_ops
 from tensorflow.python.data.ops import dataset_ops
@@ -231,7 +231,7 @@ def __init__(self, client_resource, selected_fields, output_types,
     # of b/141251314
     sorted_fields_with_types = sorted(
         zip(selected_fields, output_types),
-        key=operator.itemgetter(0))
+        key=itemgetter(0))
     selected_fields, output_types = list(zip(*sorted_fields_with_types))
     selected_fields = list(selected_fields)
     output_types = list(output_types)