parameters: (self, key)
docstring: If the keyed message exists, remove it.
docstring_summary: If the keyed message exists, remove it.
docstring_tokens: If the keyed message exists remove it .
function: def discard(self, key):
          """If the keyed message exists, remove it."""
          try:
              self.remove(key)
          except KeyError:
              pass
function_tokens: def discard ( self , key ) : try : self . remove ( key ) except KeyError : pass