Get a unique list of items that occur more than once in a list

Question

I have a list of items:

mylist = [\'A\',\'A\',\'B\',\'C\',\'D\',\'E\',\'D\']

I want to return a unique list of items that appear more than

Answer 1

>>> mylist = ['A','A','B','C','D','E','D']
>>> set([i for i in mylist if mylist.count(i)>1])
set(['A', 'D'])