add `import grpc` in test_client script

python/examples/grpc_impl_example/fit_a_line/test_asyn_client.py

@@ -18,6 +18,7 @@ import paddle
 import functools
 import time
 import threading
+import grpc
 
 client = Client()
 client.connect(["127.0.0.1:9393"])

python/examples/grpc_impl_example/fit_a_line/test_batch_client.py

@@ -15,6 +15,7 @@
 
 from paddle_serving_client import MultiLangClient as Client
 import paddle
+import grpc
 
 client = Client()
 client.connect(["127.0.0.1:9393"])

python/examples/grpc_impl_example/fit_a_line/test_general_pb_client.py

@@ -14,6 +14,7 @@
 # pylint: disable=doc-string-missing
 
 from paddle_serving_client import MultiLangClient as Client
+import grpc
 import paddle
 
 client = Client()

python/examples/grpc_impl_example/fit_a_line/test_list_input_client.py

@@ -14,6 +14,7 @@
 # pylint: disable=doc-string-missing
 
 from paddle_serving_client import MultiLangClient as Client
+import grpc
 import paddle
 
 client = Client()

python/examples/grpc_impl_example/fit_a_line/test_sync_client.py

@@ -15,6 +15,7 @@
 
 from paddle_serving_client import MultiLangClient as Client
 import paddle
+import grpc
 
 client = Client()
 client.connect(["127.0.0.1:9393"])