diff --git a/src/cpl_core/dependency_injection/service_collection.py b/src/cpl_core/dependency_injection/service_collection.py
index 337f172a..1b428a8c 100644
--- a/src/cpl_core/dependency_injection/service_collection.py
+++ b/src/cpl_core/dependency_injection/service_collection.py
@@ -10,7 +10,6 @@ from cpl_core.dependency_injection.service_lifetime_enum import ServiceLifetimeE
 from cpl_core.dependency_injection.service_provider import ServiceProvider
 from cpl_core.logging.logger_service import Logger
 from cpl_core.logging.logger_abc import LoggerABC
-from cpl_core.utils.credential_manager import CredentialManager
 
 
 class ServiceCollection(ServiceCollectionABC):
@@ -59,12 +58,15 @@ class ServiceCollection(ServiceCollectionABC):
 
             self._add_descriptor(impl, ServiceLifetimeEnum.singleton)
 
+        return self
+
     def add_scoped(self, service_type: Type, service: Callable = None):
         if service is not None:
             self._add_descriptor(service, ServiceLifetimeEnum.scoped)
         else:
             self._add_descriptor(service_type, ServiceLifetimeEnum.scoped)
-        
+
+        return self
 
     def add_transient(self, service_type: type, service: type = None):
         if service is not None:
@@ -72,5 +74,7 @@ class ServiceCollection(ServiceCollectionABC):
         else:
             self._add_descriptor(service_type, ServiceLifetimeEnum.transient)
 
+        return self
+
     def build_service_provider(self) -> ServiceProviderABC:
         return ServiceProvider(self._service_descriptors, self._configuration, self._database_context)
diff --git a/src/cpl_core/dependency_injection/service_collection_abc.py b/src/cpl_core/dependency_injection/service_collection_abc.py
index 2f69691a..13ddca96 100644
--- a/src/cpl_core/dependency_injection/service_collection_abc.py
+++ b/src/cpl_core/dependency_injection/service_collection_abc.py
@@ -31,7 +31,7 @@ class ServiceCollectionABC(ABC):
         pass
 
     @abstractmethod
-    def add_transient(self, service_type: Type, service: Callable = None):
+    def add_transient(self, service_type: Type, service: Callable = None) -> 'ServiceCollectionABC':
         r"""Adds a service with transient lifetime
 
         Parameter
@@ -40,11 +40,15 @@ class ServiceCollectionABC(ABC):
                 Type of the service
             service: :class:`Callable`
                 Object of the service
+
+        Returns
+        ------
+            self: :class:`cpl_core.dependency_injection.service_collection_abc.ServiceCollectionABC
         """
         pass
 
     @abstractmethod
-    def add_scoped(self, service_type: Type, service: Callable = None):
+    def add_scoped(self, service_type: Type, service: Callable = None) -> 'ServiceCollectionABC':
         r"""Adds a service with scoped lifetime
 
         Parameter
@@ -53,11 +57,15 @@ class ServiceCollectionABC(ABC):
                 Type of the service
             service: :class:`Callable`
                 Object of the service
+
+        Returns
+        ------
+            self: :class:`cpl_core.dependency_injection.service_collection_abc.ServiceCollectionABC
         """
         pass
 
     @abstractmethod
-    def add_singleton(self, service_type: Type, service: Callable = None):
+    def add_singleton(self, service_type: Type, service: Callable = None) -> 'ServiceCollectionABC':
         r"""Adds a service with singleton lifetime
 
         Parameter
@@ -66,6 +74,10 @@ class ServiceCollectionABC(ABC):
                 Type of the service
             service: :class:`Callable`
                 Object of the service
+
+        Returns
+        ------
+            self: :class:`cpl_core.dependency_injection.service_collection_abc.ServiceCollectionABC
         """
         pass