def _actual_key(self, key):
        """Translate provided key into the key used in the topology. Tries the unmodified key, the key with the default namespace, and the country converter. Raises a ``KeyError`` if none of these finds a suitable definition in ``self.topology``."""
        if key in self or key in ("RoW", "GLO"):
            return key
        elif (self.default_namespace, key) in self:
            return (self.default_namespace, key)

        if isinstance(key, str) and self.coco:
            new = coco.convert(names=[key], to='ISO2', not_found=None)
            if new in self:
                if new not in self.__seen:
                    self.__seen.add(key)
                    print("Geomatcher: Used '{}' for '{}'".format(new, key))
                return new

        raise KeyError("Can't find this location")
Translate provided key into the key used in the topology. Tries the unmodified key, the key with the default namespace, and the country converter. Raises a ``KeyError`` if none of these finds a suitable definition in ``self.topology``.