chore: enhance typing and documentation in tasks module (#3467)

- Disable E501 line length linting rule
- Add Google-style docstrings to tasks leaf file
- Modernize typing and docs in task_output.py
- Improve typing and documentation in conditional_task.py

src/crewai/tasks/conditional_task.py

@@ -1,4 +1,7 @@
-from typing import Any, Callable
+"""Conditional task execution based on previous task output."""
+
+from collections.abc import Callable
+from typing import Any
 
 from pydantic import Field
 
@@ -8,37 +11,54 @@ from crewai.tasks.task_output import TaskOutput
 
 
 class ConditionalTask(Task):
-    """
-    A task that can be conditionally executed based on the output of another task.
-    Note: This cannot be the only task you have in your crew and cannot be the first since its needs context from the previous task.
+    """A task that can be conditionally executed based on the output of another task.
+
+    This task type allows for dynamic workflow execution based on the results of
+    previous tasks in the crew execution chain.
+
+    Attributes:
+        condition: Function that evaluates previous task output to determine execution.
+
+    Notes:
+        - Cannot be the only task in your crew
+        - Cannot be the first task since it needs context from the previous task
     """
 
-    condition: Callable[[TaskOutput], bool] = Field(
+    condition: Callable[[TaskOutput], bool] | None = Field(
         default=None,
-        description="Maximum number of retries for an agent to execute a task when an error occurs.",
+        description="Function that determines whether the task should be executed based on previous task output.",
     )
 
     def __init__(
         self,
-        condition: Callable[[Any], bool],
+        condition: Callable[[Any], bool] | None = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
         self.condition = condition
 
     def should_execute(self, context: TaskOutput) -> bool:
-        """
-        Determines whether the conditional task should be executed based on the provided context.
+        """Determines whether the conditional task should be executed based on the provided context.
 
         Args:
-            context (Any): The context or output from the previous task that will be evaluated by the condition.
+            context: The output from the previous task that will be evaluated by the condition.
 
         Returns:
-            bool: True if the task should be executed, False otherwise.
+            True if the task should be executed, False otherwise.
+
+        Raises:
+            ValueError: If no condition function is set.
         """
+        if self.condition is None:
+            raise ValueError("No condition function set for conditional task")
         return self.condition(context)
 
-    def get_skipped_task_output(self):
+    def get_skipped_task_output(self) -> TaskOutput:
+        """Generate a TaskOutput for when the conditional task is skipped.
+
+        Returns:
+            Empty TaskOutput with RAW format indicating the task was skipped.
+        """
         return TaskOutput(
             description=self.description,
             raw="",