parameters: (self, key, message)
docstring: Replace the keyed message; raise KeyError if it doesn't exist.
docstring_summary: Replace the keyed message; raise KeyError if it doesn't exist.
docstring_tokens: Replace the keyed message ; raise KeyError if it doesn t exist .
function: def __setitem__(self, key, message):
          """Replace the keyed message; raise KeyError if it doesn't exist."""
          raise NotImplementedError('Method must be implemented by subclass')
function_tokens: def __setitem__ ( self , key , message ) : raise NotImplementedError ( 'Method must be implemented by subclass' )