Added comments to application

src/cpl/application/startup_abc.py

@@ -8,13 +8,32 @@ from cpl.dependency_injection.service_provider_abc import ServiceProviderABC
 class StartupABC(ABC):
 
     @abstractmethod
-    def __init__(self): pass
+    def __init__(self):
+        """
+        ABC for a startup class
+        """
+        pass
 
     @abstractmethod
-    def create_application_host(self) -> ApplicationHostABC: pass
+    def create_application_host(self) -> ApplicationHostABC:
+        """
+        Creates application host with specific attributes
+        :return: application host
+        """
+        pass
 
     @abstractmethod
-    def create_configuration(self) -> ConfigurationABC: pass
+    def create_configuration(self) -> ConfigurationABC:
+        """
+        Creates configuration of application
+        :return: configuration
+        """
+        pass
 
     @abstractmethod
-    def create_services(self) -> ServiceProviderABC: pass
+    def create_services(self) -> ServiceProviderABC:
+        """
+        Creates service provider
+        :return: service provider
+        """
+        pass