diff --git a/README.md b/README.md
index 0fd5187..8483f8c 100644
--- a/README.md
+++ b/README.md
@@ -72,9 +72,9 @@ def example():
     )
 
     #  Retrieve API secret information from environment variables
-    key = os.getenv("API_KEY")
-    secret = os.getenv("API_SECRET")
-    passphrase = os.getenv("API_PASSPHRASE")
+    key = os.getenv("API_KEY", "")
+    secret = os.getenv("API_SECRET", "")
+    passphrase = os.getenv("API_PASSPHRASE", "")
 
     # Set specific options, others will fall back to default values
     http_transport_option = (
diff --git a/sdk/python/README.md b/sdk/python/README.md
index 17e411b..35caf58 100644
--- a/sdk/python/README.md
+++ b/sdk/python/README.md
@@ -36,9 +36,9 @@ def example():
     )
 
     #  Retrieve API secret information from environment variables
-    key = os.getenv("API_KEY")
-    secret = os.getenv("API_SECRET")
-    passphrase = os.getenv("API_PASSPHRASE")
+    key = os.getenv("API_KEY", "")
+    secret = os.getenv("API_SECRET", "")
+    passphrase = os.getenv("API_PASSPHRASE", "")
 
     # Set specific options, others will fall back to default values
     http_transport_option = (
diff --git a/sdk/python/example/example_api.py b/sdk/python/example/example_api.py
index a17eac6..edebfaa 100644
--- a/sdk/python/example/example_api.py
+++ b/sdk/python/example/example_api.py
@@ -27,9 +27,9 @@ def rest_example():
     )
 
     #  Retrieve API secret information from environment variables
-    key = os.getenv("API_KEY")
-    secret = os.getenv("API_SECRET")
-    passphrase = os.getenv("API_PASSPHRASE")
+    key = os.getenv("API_KEY", "")
+    secret = os.getenv("API_SECRET", "")
+    passphrase = os.getenv("API_PASSPHRASE", "")
 
     # Optional: Retrieve broker secret information from environment variables; applicable for broker API only
     broker_name = os.getenv("BROKER_NAME")
diff --git a/sdk/python/example/example_get_started.py b/sdk/python/example/example_get_started.py
index 124e558..15dd5c4 100644
--- a/sdk/python/example/example_get_started.py
+++ b/sdk/python/example/example_get_started.py
@@ -17,9 +17,9 @@ def example():
     )
 
     #  Retrieve API secret information from environment variables
-    key = os.getenv("API_KEY")
-    secret = os.getenv("API_SECRET")
-    passphrase = os.getenv("API_PASSPHRASE")
+    key = os.getenv("API_KEY", "")
+    secret = os.getenv("API_SECRET", "")
+    passphrase = os.getenv("API_PASSPHRASE", "")
 
     # Set specific options, others will fall back to default values
     http_transport_option = (
diff --git a/sdk/python/example/example_ws.py b/sdk/python/example/example_ws.py
index 0eb310d..52e7959 100644
--- a/sdk/python/example/example_ws.py
+++ b/sdk/python/example/example_ws.py
@@ -21,9 +21,9 @@ def ws_example():
     )
 
     # Retrieve API secret information from environment variables
-    key = os.getenv("API_KEY")
-    secret = os.getenv("API_SECRET")
-    passphrase = os.getenv("API_PASSPHRASE")
+    key = os.getenv("API_KEY", "")
+    secret = os.getenv("API_SECRET", "")
+    passphrase = os.getenv("API_PASSPHRASE", "")
 
     # Set specific options, others will fall back to default values
     ws_client_option = (
diff --git a/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_service.py b/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_service.py
index 104315b..4686b5a 100644
--- a/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_service.py
+++ b/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_service.py
@@ -17,8 +17,8 @@
 from ..util.sub import SubInfo
 
 class DefaultWsService(WebSocketService):
-    def __init__(self, client_option: ClientOption, domain: DomainType, private: bool):
-        self.token_transport = DefaultTransport(client_option)
+    def __init__(self, client_option: ClientOption, domain: DomainType, private: bool, sdk_version:str):
+        self.token_transport = DefaultTransport(client_option, sdk_version)
         ws_option = client_option.websocket_client_option
 
         self.client = WebSocketClient(DefaultWsTokenProvider(self.token_transport, domain, private), ws_option)
diff --git a/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_token_provider.py b/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_token_provider.py
index fe92554..f43204a 100644
--- a/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_token_provider.py
+++ b/sdk/python/kucoin_universal_sdk/internal/infra/default_ws_token_provider.py
@@ -7,13 +7,13 @@
 from kucoin_universal_sdk.model.common import RestResponse
 from kucoin_universal_sdk.model.constants import DomainType
 from .default_transport import DefaultTransport
-from ..interfaces.websocket import WsToken
+from ..interfaces.websocket import WsToken, WsTokenProvider
 
 PATH_PRIVATE = "/api/v1/bullet-private"
 PATH_PUBLIC = "/api/v1/bullet-public"
 
 
-class DefaultWsTokenProvider:
+class DefaultWsTokenProvider(WsTokenProvider):
     def __init__(self, transport: DefaultTransport, domain: DomainType, private: bool):
         self.transport = transport
         self.domain = domain
diff --git a/sdk/python/setup.py b/sdk/python/setup.py
index f7900ec..da0fb0e 100644
--- a/sdk/python/setup.py
+++ b/sdk/python/setup.py
@@ -2,7 +2,7 @@
 
 setup(
     name="kucoin-universal-sdk",
-    version="0.1.0a1",
+    version="0.1.0a2",
     description="Official KuCoin Universal SDK",
     author="KuCoin",
     author_email="api@kucoin.com",