feat: Add method create_task to the TaskManager class

src/retsu/core.py

@@ -136,6 +136,17 @@ def __init__(self) -> None:
         """Create a list of retsu tasks."""
         self.tasks: dict[str, Task] = {}
 
+    @public
+    def create_tasks(self) -> None:
+        """Get a task with the given name."""
+        if self.tasks:
+            return
+
+        warnings.warn(
+            "`self.tasks` is empty. Override `create_tasks` and create "
+            "`self.tasks` with the proper tasks."
+        )
+
     @public
     def get_task(self, name: str) -> Optional[Task]:
         """Get a task with the given name."""
@@ -144,13 +155,20 @@ def get_task(self, name: str) -> Optional[Task]:
     @public
     def start(self) -> None:
         """Start tasks."""
+        if not self.tasks:
+            self.create_tasks()
+
         for task_name, task in self.tasks.items():
             print(f"Task `{task_name}` is starting ...")
             task.start()
 
     @public
     def stop(self) -> None:
         """Stop tasks."""
+        if not self.tasks:
+            warnings.warn("There is no tasks to be stopped.")
+            return
+
         for task_name, task in self.tasks.items():
             print(f"Task `{task_name}` is stopping ...")
             task.stop()