Trouble branching DAGs in Airflow Taskflow API - airflow

Question

I am new to Airflow. Using Taskflow API, I am trying to dynamically change the flow of DAGs. If a condition is met, the two step workflow should be executed a second time.
After defining two functions/tasks, if I fix the DAG sequence as below, everything works fine.
#dag(default_args=default_args, schedule_interval=None, start_date=days_ago(2))
def genesis(**kwargs):
#task()
def extract():
print("X")
#task()
def add_timeframe():
print("Y")
extracted_data = extract()
timeframe_data = add_timeframe(extracted_data)
However, I write any conditional logic to trigger the second run (either inside a DAG or after the function/task definitions), I get the error below. The error seems to be about setting upstream tasks. But the older "task.set_upstream(task2)" commands don't work in Taskflow Airflow 2.0.
All examples I could find of conditionally branching were based on the non Taskflow API. Please help.
#dag(default_args=default_args, schedule_interval=None, start_date=days_ago(2))
def genesis(**kwargs):
#task()
def extract():
print("X")
if <condition>:
extracted_data2 = extract()
timeframe_data2 = add_timeframe(extracted_data2)
#task()
def add_timeframe():
print("Y")
extracted_data = extract()
timeframe_data = add_timeframe(extracted_data)
ERROR - Tried to create relationships between tasks that don't have DAGs yet. Set the DAG for at least one task and try again: [<Task(_PythonDecoratedOperator): add_timeframe>, <Task(_PythonDecoratedOperator): extract>]
Traceback (most recent call last):
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1086, in _run_raw_task
self._prepare_and_execute_task_with_callbacks(context, task)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1260, in _prepare_and_execute_task_with_callbacks
result = self._execute_task(context, task_copy)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 1300, in _execute_task
result = task_copy.execute(context=context)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/operators/python.py", line 233, in execute
return_value = self.python_callable(*self.op_args, **self.op_kwargs)
File "/opt/airflow/dags/genesis.py", line 77, in extract
timeframe_data = add_timeframe(extracted_data)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/operators/python.py", line 294, in factory
**kwargs,
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/baseoperator.py", line 91, in __call__
obj.set_xcomargs_dependencies()
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/baseoperator.py", line 722, in set_xcomargs_dependencies
apply_set_upstream(arg)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/baseoperator.py", line 711, in apply_set_upstream
apply_set_upstream(elem)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/baseoperator.py", line 708, in apply_set_upstream
self.set_upstream(arg.operator)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/baseoperator.py", line 1239, in set_upstream
self._set_relatives(task_or_task_list, upstream=True)
File "/home/ubuntu/anaconda3/lib/python3.7/site-packages/airflow/models/baseoperator.py", line 1205, in _set_relatives
"task and try again: {}".format([self] + task_list)