replay() fails when not list

[prjemian]

In [4]: APS_utils.replay(db[-1], handler)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-4-731a69b7fda4> in <module>
----> 1 APS_utils.replay(db[-1], handler)

/share1/bluesky/conda_envs/bluesky/lib/python3.7/site-packages/apstools/utils.py in replay(headers, callback)
    362         if not isinstance(h, databroker.Header):
    363             emsg = f"Must be a databroker Header: received: {type(h)}: |{h}|"
--> 364             raise TypeError(emsg)
    365         cmd = _rebuild_scan_command(h.start)
    366         logger.debug(f"{cmd}")

TypeError: Must be a databroker Header: received: <class 'str'>: |start|

[prjemian]

But this works: APS_utils.replay([db[-1]], handler)