passing port_grpc in search function leads to a TypeError  
**Describe the bug**
check the bug at [issue-34](https://github.com/jina-ai/examples/issues/34)

**Describe how you solve it**
avoid passing `port_grpc` as a keyword argument because the `**kwargs` has already included it.

---

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**Environment**
<!-- Run `jina --version-full` and copy paste the output here -->

**Screenshots**
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diff --git a/jina/executors/__init__.py b/jina/executors/__init__.py
index 5bbe321eda0..a862009ee4c 100644
--- a/jina/executors/__init__.py
+++ b/jina/executors/__init__.py
@@ -21,6 +21,9 @@ from ..helper import yaml, PathImporter, expand_dict, expand_env_var, valid_yaml
 from ..logging.base import get_logger
 from ..logging.profile import TimeContext
 
+if False:
+    from ..drivers import BaseDriver
+
 __all__ = ['BaseExecutor', 'AnyExecutor', 'ExecutorType']
 
 AnyExecutor = TypeVar('AnyExecutor', bound='BaseExecutor')
diff --git a/jina/flow/__init__.py b/jina/flow/__init__.py
index 327a6b62e1d..7ef43c4b90b 100644
--- a/jina/flow/__init__.py
+++ b/jina/flow/__init__.py
@@ -519,7 +519,11 @@ class Flow:
     def _get_client(self, **kwargs):
         kwargs.update(self._common_kwargs)
         from ..clients import py_client
-        return py_client(port_grpc=self.port_grpc, host=self.host, **kwargs)
+        if 'port_grpc' not in kwargs:
+            kwargs['port_grpc'] = self.port_grpc
+        if 'host' not in kwargs:
+            kwargs['host'] = self.host
+        return py_client(**kwargs)
 
     @deprecated_alias(raw_bytes='input_fn', callback='output_fn')
     def train(self, input_fn: Union[Iterator['jina_pb2.Document'], Iterator[bytes], Callable] = None,
['jina/flow/__init__.py', 'jina/executors/__init__.py']