get_detail_data_frame() fails when passed list of DetailEvent objects

[johndwest]

Describe the bug
documentation states that get_detail_data_frame() accepts a list of DetailEvent objects
documentation states that DetailEvent objects can be acquired using the get_event_by_id() method
BUT: get_detail_data_frame() fails when passed a list of DetailEvent objects, works when passed a list of SummaryEvent objects

To Reproduce
ThisEvent = 'ak01613v15nv'
try:
detailE = get_event_by_id(eventid=ThisEvent)
DummyList = []
DummyList.append(detailE)
moment_df = get_detail_data_frame(events=DummyList, get_tensors='preferred')
except Exception as ex:
MsgText = "ADEPT script error retrieving moment tensors."
print(MsgText, str(ex) + traceback.format_exc())

Expected behavior
Per the documentation I expect get_detail_data_frame() to return a dataframe containing data for the chosen DetailEvent. It fails.

Environment (please complete the following information):
OS: Ubuntu 20.04.1 LTS
Python Version 3.8
Libcomcat Version 2.0
Numpy Version 1.20.3

Additional context
Source code file dataframes.py, line 348 assumes that the event list passed to get_detail_data_frame() is a list of SummaryEvent objects, contrary to the documentation and the needs of anyone trying to get the moment tensor solution for a single event. I suggest the code in this module should check to see if the passed objects are already DetailEvent objects before trying to convert them to DetailEvents.

As an additional suggestion: it might be nice if the function would accept a single DetailEvent object instead of requiring the user to put the object in a list of one item.