diff --git a/vnpy/api/rest/rest_client.py b/vnpy/api/rest/rest_client.py
index 008b4c7f..df7b6ea7 100644
--- a/vnpy/api/rest/rest_client.py
+++ b/vnpy/api/rest/rest_client.py
@@ -374,7 +374,7 @@ class RestClient(object):
                 request.response = response
                 status_code = response.status_code
 
-                if not stream: # normal API:
+                if not stream:  # normal API:
                     # just call callback with all contents received.
                     if status_code // 100 == 2:  # 2xx codes are all successful
                         if status_code == 204:
@@ -388,7 +388,7 @@ class RestClient(object):
                             request.on_failed(status_code, request)
                         else:
                             self.on_failed(status_code, request)
-                else: # streaming API:
+                else:  # streaming API:
                     if request.on_connected:
                         request.on_connected(request)
                     # split response by lines, and call one callback for each line.
diff --git a/vnpy/gateway/oanda/oanda_api_base.py b/vnpy/gateway/oanda/oanda_api_base.py
index 2182187b..c3fe192f 100644
--- a/vnpy/gateway/oanda/oanda_api_base.py
+++ b/vnpy/gateway/oanda/oanda_api_base.py
@@ -1,22 +1,11 @@
 import json
 import sys
-from dataclasses import dataclass
-from datetime import datetime
-from threading import Lock
-from typing import Dict, List, Optional, TYPE_CHECKING, Tuple
+from typing import TYPE_CHECKING
 
-from requests import ConnectionError
-
-from vnpy.api.rest import Request
-from vnpy.trader.constant import Direction, Exchange, Interval, Offset, Product, Status
-from vnpy.trader.object import AccountData, BarData, CancelRequest, ContractData, OrderRequest, \
-    PositionData, OrderData
-from .oanda_common import (INTERVAL_VT2OANDA, ORDER_TYPE_VT2OANDA,
-                           STATUS_OANDA2VT, parse_time, INTERVAL_VT2OANDA_DELTA, parse_datetime)
+from vnpy.api.rest import Request, RestClient
 
 if TYPE_CHECKING:
     from vnpy.gateway.oanda import OandaGateway
-from vnpy.api.rest import RestClient
 
 _ = lambda x: x  # noqa
 
@@ -25,6 +14,7 @@ class OandaApiBase(RestClient):
     """
     Oanda Base API
     """
+
     def __init__(self, gateway: "OandaGateway"):
         super().__init__()
         self.gateway = gateway
@@ -62,4 +52,3 @@ class OandaApiBase(RestClient):
         sys.stderr.write(
             self.exception_detail(exception_type, exception_value, tb, request)
         )
-
diff --git a/vnpy/gateway/oanda/oanda_common.py b/vnpy/gateway/oanda/oanda_common.py
index 59cbcabe..968063c7 100644
--- a/vnpy/gateway/oanda/oanda_common.py
+++ b/vnpy/gateway/oanda/oanda_common.py
@@ -6,7 +6,7 @@ from vnpy.trader.constant import Direction, Interval, OrderType, Status
 
 if TYPE_CHECKING:
     # noinspection PyUnresolvedReferences
-    from vnpy.gateway.oanda import OandaGateway
+    from vnpy.gateway.oanda import OandaGateway  # noqa
 
 STATUS_OANDA2VT = {
     "PENDING": Status.NOTTRADED,
diff --git a/vnpy/gateway/oanda/oanda_gateway.py b/vnpy/gateway/oanda/oanda_gateway.py
index 9a602e3a..f099ac69 100644
--- a/vnpy/gateway/oanda/oanda_gateway.py
+++ b/vnpy/gateway/oanda/oanda_gateway.py
@@ -5,22 +5,19 @@ todo:
 """
 from dataclasses import dataclass
 from datetime import datetime
-from typing import Dict, List, Any, Tuple, Optional
+from typing import Any, Dict, List, Optional, Tuple
 
 from vnpy.event import Event
-from vnpy.trader.constant import (Exchange, OrderType, Interval, Direction, Offset, Status)
+from vnpy.trader.constant import (Direction, Exchange, Interval, Offset, OrderType, Status)
 from vnpy.trader.event import EVENT_TIMER
 from vnpy.trader.gateway import BaseGateway
-from vnpy.trader.object import (CancelRequest, HistoryRequest, OrderData, OrderRequest,
-                                PositionData, SubscribeRequest, TickData, BarData)
-from .oanda_common import DIRECTION_OANDA2VT, OPPOSITE_DIRECTION, ORDER_TYPE_OANDA2VT, \
-    STOP_ORDER_STATUS_OANDA2VT, parse_datetime, STATUS_OANDA2VT, INTERVAL_VT2OANDA, local_tz, \
-    utc_tz, INTERVAL_VT2OANDA_INT, parse_time, INTERVAL_VT2OANDA_DELTA
-from .oanda_rest_api import OandaRestApi, HistoryDataNextInfo
+from vnpy.trader.object import (BarData, CancelRequest, HistoryRequest, OrderData, OrderRequest,
+                                SubscribeRequest)
+from .oanda_common import INTERVAL_VT2OANDA_DELTA, ORDER_TYPE_OANDA2VT, local_tz, parse_time, utc_tz
+from .oanda_rest_api import HistoryDataNextInfo, OandaRestApi
 from .oanda_stream_api import OandaStreamApi
 
-
-_ = lambda x:x  # noqa
+_ = lambda x: x  # noqa
 
 
 @dataclass()
@@ -99,10 +96,10 @@ class OandaGateway(BaseGateway):
         self.rest_api.query_positions()
 
     def query_first_history(self,
-                          symbol: str,
-                          interval: Interval,
-                          start: datetime,
-                          ) -> Tuple[List[BarData], "HistoryDataNextInfo"]:
+                            symbol: str,
+                            interval: Interval,
+                            start: datetime,
+                            ) -> Tuple[List[BarData], "HistoryDataNextInfo"]:
 
         # datetime for a bar is close_time
         # we got open_time from API.
@@ -205,4 +202,3 @@ class OandaGateway(BaseGateway):
         )
         self.orders[order_id] = order
         return order
-
diff --git a/vnpy/gateway/oanda/oanda_rest_api.py b/vnpy/gateway/oanda/oanda_rest_api.py
index ceb4cf79..852931c8 100644
--- a/vnpy/gateway/oanda/oanda_rest_api.py
+++ b/vnpy/gateway/oanda/oanda_rest_api.py
@@ -1,5 +1,3 @@
-import json
-import sys
 from dataclasses import dataclass
 from datetime import datetime
 from threading import Lock
@@ -11,10 +9,9 @@ from vnpy.api.rest import Request
 from vnpy.gateway.oanda.oanda_api_base import OandaApiBase
 from vnpy.trader.constant import Direction, Exchange, Interval, Offset, Product, Status
 from vnpy.trader.object import AccountData, BarData, CancelRequest, ContractData, OrderRequest, \
-    PositionData, OrderData
-from .oanda_common import (INTERVAL_VT2OANDA, ORDER_TYPE_VT2OANDA,
-                           STATUS_OANDA2VT, parse_time, INTERVAL_VT2OANDA_DELTA, parse_datetime,
-                           utc_tz, local_tz)
+    PositionData
+from .oanda_common import (INTERVAL_VT2OANDA, INTERVAL_VT2OANDA_DELTA, ORDER_TYPE_VT2OANDA,
+                           STATUS_OANDA2VT, local_tz, parse_datetime, parse_time, utc_tz)
 
 if TYPE_CHECKING:
     from vnpy.gateway.oanda import OandaGateway
@@ -122,7 +119,6 @@ class OandaRestApi(OandaApiBase):
         order.time = parse_time(datetime.now().isoformat())
 
         # Only add price for limit order.
-        str_price = str(req.price)
         data["type"] = ORDER_TYPE_VT2OANDA[req.type]
         data["price"] = str(req.price)
         self.gateway.orders[order.orderid] = order
@@ -240,7 +236,7 @@ class OandaRestApi(OandaApiBase):
 
     def on_send_order(self, raw_data: dict, request: Request):
         """"""
-        order: OrderData = request.extra
+        # order: OrderData = request.extra
         # creation = raw_data.get('orderCreateTransaction', None)
         # if creation is not None:
         #     order.status = Status.NOTTRADED
@@ -314,7 +310,7 @@ class OandaRestApi(OandaApiBase):
             gateway_name=self.gateway_name,
             accountid=account_id,
             balance=NAV - pnl,
-            frozen=0, # no frozen
+            frozen=0,  # no frozen
         )
         self.gateway.on_account(account)
 
@@ -347,15 +343,16 @@ class OandaRestApi(OandaApiBase):
 
     def parse_position_data(self, pos_data) -> Tuple[PositionData, PositionData]:
         symbol = pos_data['instrument']
-        pos_long, pos_short = [PositionData(
-            gateway_name=self.gateway_name,
-            symbol=symbol,
-            exchange=Exchange.OANDA,
-            direction=direction,
-            volume=int(data['units']),
-            price=float(data.get('averagePrice', 0.0)),
-            pnl=float(data.get('unrealizedPL', 0.0)),
-        )
+        pos_long, pos_short = [
+            PositionData(
+                gateway_name=self.gateway_name,
+                symbol=symbol,
+                exchange=Exchange.OANDA,
+                direction=direction,
+                volume=int(data['units']),
+                price=float(data.get('averagePrice', 0.0)),
+                pnl=float(data.get('unrealizedPL', 0.0)),
+            )
             for direction, data in (
                 (Direction.LONG, pos_data['long']),
                 (Direction.SHORT, pos_data['short'])
diff --git a/vnpy/gateway/oanda/oanda_stream_api.py b/vnpy/gateway/oanda/oanda_stream_api.py
index 5c3cab06..4a433d02 100644
--- a/vnpy/gateway/oanda/oanda_stream_api.py
+++ b/vnpy/gateway/oanda/oanda_stream_api.py
@@ -1,5 +1,4 @@
 from copy import copy
-from copy import copy
 from dataclasses import dataclass
 from functools import partial
 from http.client import IncompleteRead, RemoteDisconnected
diff --git a/vnpy/trader/constant.py b/vnpy/trader/constant.py
index 57b8e631..a7ce039a 100644
--- a/vnpy/trader/constant.py
+++ b/vnpy/trader/constant.py
@@ -119,6 +119,7 @@ class Exchange(Enum):
     BINANCE = "BINANCE"
     COINBASE = "COINBASE"
 
+
 class Currency(Enum):
     """
     Currency.