def duplicate(
            self, 
            key: str, 
            new_key: str,
        ) -> None:
        """
        Duplicate a key to a new key.

        Parameters
        ----------
        key : str
            Name of the key to duplicated.
        new_key : str
            Name of the key to which to duplicate the original key.
        """
        self.set(new_key, self.get(key))

        Duplicate a key to a new key.

        Parameters
        ----------
        key : str
            Name of the key to duplicated.
        new_key : str
            Name of the key to which to duplicate the original key.
        
pymoo/core/individual.py