sorting a list of dicts by a computed field

[Larry Martell]

I have a list of dicts and one item of the dict is a date in m/d/Y
format. I want to sort by that. I tried this:

sorted(data['trends'], key=lambda k:
datetime.strptime(k['date_time'],'%m/%d/%Y'))

But that fails with:

Exception Type: AttributeError at /report/CDSEM/WaferAlignment/ajax/waChart.json
Exception Value: 'module' object has no attribute 'strptime'

How can I do this sort?