          try:
              self.remove(item)
  
      def __iter__(self):
          return iter(self.dict)
  
      def __contains__(self, item):
 
</s> remove         with suppress(KeyError):
 </s> add         try: </s> remove             with suppress(SystemExit):
 </s> add             try: </s> remove         with suppress(KeyError):
 </s> add         try:
        except KeyError:
            pass
          try:
              self.remove(item)
        except KeyError:
            pass
  
      def __iter__(self):
          return iter(self.dict)
  
      def __contains__(self, item):
keep add keep keep keep keep keep
 Reverted "Fixed #27818 -- Replaced try/except/pass with contextlib.suppress()."

This reverts commit 550cb3a365dee4edfdd1563224d5304de2a57fda
because try/except performs better. 
django/utils/datastructures.py