Feature Request: Transform excepting dicts and lists after groupby

[Make42]

@WillAyd
Just so I'm clear, you're suggesting something like:
test.groupby('groups').transform({'value1': [np.mean, max], 'value2': max}) which should return something like:

                    value1     value2    
                      mean max   max
2012-02-01 14:00:00      2   3    30
2012-02-01 14:01:00      2   3    30
2012-03-05 14:04:00      2   3    30
2012-03-05 14:01:00      5   6    60
2012-03-10 14:02:00      5   6    60
2012-03-11 14:07:50      5   6    60

Originally posted by @brianhuey in #17309 (comment)

Exactly this is my feature request.

[WillAyd]

If you have a PR for the issue linked feel free to push.

Closing this as duplicate (don't need a new issue)