**Description**
The `airflow.models.baseoperator.chain()` is a very useful and convenient way to add sequential task dependencies in DAGs.  This function has [recently been updated](https://github.com/apache/airflow/issues/16635) to support `BaseOperator` and `XComArgs` but should also be able to support `Labels` as well.

**Use case / motivation**
Users who create tasks via the `@task` decorator will not be able to use the `chain()` function to apply sequential dependencies that do not share an `XComArg` implicit dependency with a `Label`.  This use case can occur when attempting to chain multiple branch labels and the next sequential task.

With the new update (yet to be released), users will receive the following exception when attempting to chain an `XComArg` and `Label`:

```bash
TypeError: Chain not supported between instances of <class 'airflow.utils.edgemodifier.EdgeModifier'> and <class 'airflow.models.xcom_arg.XComArg'>
```


**Are you willing to submit a PR?**
Absolutely. 🚀 

**Related Issues**
None

airflow/models/baseoperator.py
"""Used to determine if an Operator is inherited from DummyOperator"""
        
        
        
        return getattr(self, '_is_dummy', False)
def chain(*tasks: Union[BaseOperator, "XComArg", Sequence[Union[BaseOperator, "XComArg"]]]):
    r"""
    Given a number of tasks, builds a dependency chain.
    This function accepts values of BaseOperator (aka tasks), XComArg, or lists containing
    either type (or a mix of both in the same list). If you want to chain between two lists you must
    ensure they have the same length.
    Using classic operators/sensors:
    .. code-block:: python
        chain(t1, [t2, t3], [t4, t5], t6)
    is equivalent to::
          / -> t2 -> t4 \
        t1               -> t6
          \ -> t3 -> t5 /
    .. code-block:: python
        t1.set_downstream(t2)
        t1.set_downstream(t3)
        t2.set_downstream(t4)
        t3.set_downstream(t5)
        t4.set_downstream(t6)
        t5.set_downstream(t6)
    Using task-decorated functions aka XComArgs:
    .. code-block:: python
        chain(x1(), [x2(), x3()], [x4(), x5()], x6())
    is equivalent to::
          / -> x2 -> x4 \