diff --git a/src/dlt/connector/client/DltGatewayClient.py b/src/dlt/connector/client/DltGatewayClient.py
index 8e2303b2c69dba1b5a313538ca28518ab1434c91..21d4df57dd5eaa72eddc147b83b6a66344e20f02 100644
--- a/src/dlt/connector/client/DltGatewayClient.py
+++ b/src/dlt/connector/client/DltGatewayClient.py
@@ -65,7 +65,7 @@ class DltGatewayClient:
         return response
 
     @RETRY_DECORATOR
-    def SubscribeToDlt(self, request: DltRecordSubscription) -> Iterator[DltRecordEvent]:
+    def SubscribeToDlt(self, request : DltRecordSubscription) -> Iterator[DltRecordEvent]:
         LOGGER.debug('SubscribeToDlt request: {:s}'.format(grpc_message_to_json_string(request)))
         response = self.stub.SubscribeToDlt(request)
         LOGGER.debug('SubscribeToDlt result: {:s}'.format(grpc_message_to_json_string(response)))
diff --git a/src/dlt/connector/service/DltConnectorServiceServicerImpl.py b/src/dlt/connector/service/DltConnectorServiceServicerImpl.py
index 2222f5a29fc81971ce521901f0a3199024f7ef0d..1885cc15351ea7b9a6d60c86b874685008d97145 100644
--- a/src/dlt/connector/service/DltConnectorServiceServicerImpl.py
+++ b/src/dlt/connector/service/DltConnectorServiceServicerImpl.py
@@ -39,15 +39,15 @@ class DltConnectorServiceServicerImpl(DltConnectorServiceServicer):
         await self.dltgateway_client.connect()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordAll(self, request: TopologyId, context: ServicerContext) -> Empty:
+    async def RecordAll(self, request : TopologyId, context : ServicerContext) -> Empty:
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordAllDevices(self, request: TopologyId, context: ServicerContext) -> Empty:
+    async def RecordAllDevices(self, request : TopologyId, context : ServicerContext) -> Empty:
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordDevice(self, request: DltDeviceId, context: ServicerContext) -> Empty:
+    async def RecordDevice(self, request : DltDeviceId, context : ServicerContext) -> Empty:
         data_json = None
         LOGGER.debug('RECORD_DEVICE = {:s}'.format(grpc_message_to_json_string(request)))
         if not request.delete:       
@@ -61,11 +61,11 @@ class DltConnectorServiceServicerImpl(DltConnectorServiceServicer):
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordAllLinks(self, request: TopologyId, context: ServicerContext) -> Empty:
+    async def RecordAllLinks(self, request : TopologyId, context : ServicerContext) -> Empty:
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordLink(self, request: DltLinkId, context: ServicerContext) -> Empty:
+    async def RecordLink(self, request : DltLinkId, context : ServicerContext) -> Empty:
         data_json = None
         LOGGER.debug('RECORD_LINK = {:s}'.format(grpc_message_to_json_string(request)))
 
@@ -80,11 +80,11 @@ class DltConnectorServiceServicerImpl(DltConnectorServiceServicer):
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordAllServices(self, request: TopologyId, context: ServicerContext) -> Empty:
+    async def RecordAllServices(self, request : TopologyId, context : ServicerContext) -> Empty:
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordService(self, request: DltServiceId, context: ServicerContext) -> Empty:
+    async def RecordService(self, request : DltServiceId, context : ServicerContext) -> Empty:
         data_json = None
         if not request.delete:
             context_client = ContextClient()
@@ -97,11 +97,11 @@ class DltConnectorServiceServicerImpl(DltConnectorServiceServicer):
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordAllSlices(self, request: TopologyId, context: ServicerContext) -> Empty:
+    async def RecordAllSlices(self, request : TopologyId, context : ServicerContext) -> Empty:
         return Empty()
 
     @safe_and_metered_rpc_method_async(METRICS_POOL, LOGGER)
-    async def RecordSlice(self, request: DltSliceId, context: ServicerContext) -> Empty:
+    async def RecordSlice(self, request : DltSliceId, context : ServicerContext) -> Empty:
         data_json = None
         if not request.delete:
             context_client = ContextClient()
@@ -114,8 +114,8 @@ class DltConnectorServiceServicerImpl(DltConnectorServiceServicer):
         return Empty()
 
     async def _record_entity(
-        self, dlt_domain_uuid: str, dlt_record_type: DltRecordTypeEnum, dlt_record_uuid: str, delete: bool,
-        data_json: Optional[str] = None
+        self, dlt_domain_uuid : str, dlt_record_type : DltRecordTypeEnum, dlt_record_uuid : str, delete : bool,
+        data_json : Optional[str] = None
     ) -> None:
         dlt_record_id = DltRecordId()
         dlt_record_id.domain_uuid.uuid = dlt_domain_uuid  # pylint: disable=no-member
diff --git a/src/dlt/connector/service/__main__.py b/src/dlt/connector/service/__main__.py
index e368f6302e25a9ec2c28de2f8ec0c8eeeeaead86..632b2f781cca42b9fcbb4cb8f9cd91a9ea60e768 100644
--- a/src/dlt/connector/service/__main__.py
+++ b/src/dlt/connector/service/__main__.py
@@ -14,6 +14,7 @@
 
 
 import logging, signal, threading, asyncio
+from typing import Optional
 from prometheus_client import start_http_server
 from common.Constants import ServiceNameEnum
 from common.Settings import (
@@ -23,7 +24,7 @@ from .event_dispatcher.DltEventDispatcher import DltEventDispatcher
 from .DltConnectorService import DltConnectorService
 
 terminate = threading.Event()
-LOGGER: logging.Logger = None
+LOGGER : Optional[logging.Logger] = None
 
 def signal_handler(signal, frame): # pylint: disable=redefined-outer-name
     LOGGER.warning('Terminate signal received')
@@ -37,7 +38,7 @@ async def main():
     LOGGER = logging.getLogger(__name__)
 
     wait_for_environment_variables([
-        get_env_var_name(ServiceNameEnum.CONTEXT, ENVVAR_SUFIX_SERVICE_HOST),
+        get_env_var_name(ServiceNameEnum.CONTEXT, ENVVAR_SUFIX_SERVICE_HOST     ),
         get_env_var_name(ServiceNameEnum.CONTEXT, ENVVAR_SUFIX_SERVICE_PORT_GRPC),
     ])
 
diff --git a/src/dlt/connector/service/tools/Checkers.py b/src/dlt/connector/service/tools/Checkers.py
index 9afb0da075bc4d9b6ea185b10e3bfd211ecb203d..5b19afcd24171767c9b1130c8cb9d594b5afa5bf 100644
--- a/src/dlt/connector/service/tools/Checkers.py
+++ b/src/dlt/connector/service/tools/Checkers.py
@@ -20,5 +20,5 @@ def record_exists(record : DltRecord) -> bool:
     exists = exists and (record.record_id.type != DLTRECORDTYPE_UNDEFINED)
     exists = exists and (len(record.record_id.record_uuid.uuid) > 0)
     #exists = exists and (record.operation != DLTRECORDOPERATION_UNDEFINED)
-    #exists = exists and (len(record.data_json) > 0) #It conflicts as sometimes records do not have a data_json.
+    #exists = exists and (len(record.data_json) > 0) # It conflicts as sometimes records do not have a data_json.
     return exists