refactor due to reviewer's comments

sky/dag.py

@@ -16,7 +16,7 @@ class Dag:
  """Dag: a user application, represented as a DAG of Tasks.
 
  This class allows users to define and manage directed acyclic graphs
- (DAGs) of tasks, representing complex workflows or pipelines.
+ (DAGs) of tasks, representing complex workflows.
 
  Examples:
  >>> import sky
@@ -26,39 +26,20 @@ class Dag:
  >>> task1 >> task2
  """
 
- def __init__(
- self,
- name: Optional[str] = None,
- tasks: Optional[List['task.Task']] = None,
- dependencies: Optional[Dict[TaskOrName, Union[List[TaskOrName],
- TaskOrName]]] = None
- ) -> None:
+ def __init__(self, name: Optional[str] = None) -> None:
  """Initialize a new DAG.
 
  Args:
  name: Optional name for the DAG.
- tasks: Optional list of Task objects to add to the DAG.
- dependencies: Optional dictionary specifying task dependencies.
- Keys are dependent tasks, values are lists of tasks
- they depend on.
  """
+
  self.name = name
  self.tasks: List['task.Task'] = []
  self._task_name_lookup: Dict[str, 'task.Task'] = {}
  self.dependencies: Dict['task.Task', Set['task.Task']] = {}
 
  self.graph = nx.DiGraph()
 
- # Add tasks
- if tasks:
- for task in tasks:
- self.add(task)
-
- # Add dependencies
- if dependencies:
- for dependent, deps in dependencies.items():
- self.set_dependencies(dependent, deps)
-
  def _get_task(self, task_or_name: TaskOrName) -> 'task.Task':
  """Get a task object from a task or its name.
 
@@ -90,12 +71,12 @@ def add(self, task: 'task.Task') -> None:
  """
  if task in self.tasks:
  raise ValueError(f'Task {task.name} already exists in the DAG.')
+ if task.name in self._task_name_lookup:
+ raise ValueError(
+ f'Task name "{task.name}" is already used in the DAG.')
  self.graph.add_node(task)
  self.tasks.append(task)
  if task.name is not None:
- if task.name in self._task_name_lookup:
- raise ValueError(
- f'Task name "{task.name}" is already used in the DAG.')
  self._task_name_lookup[task.name] = task
 
  def remove(self, task: Union['task.Task', str]) -> None: