def __copy__(self):
        """Duplicate object per the copy protocol."""
        newmap = self.__class__()
        # We can't just use 'update' because we want copies of the
        # mutable values (each is a list) as well.
        for k, v in self.items():
            newmap[k] = v[:]
        return newmap
Duplicate object per the copy protocol.
cherrypy/_cprequest.py