'Install a *registry* (a imputils.Registry instance) of function
and attribute implementations.'

def install_registry(self, registry):

    try:
        loader = self._registries[registry]
    except KeyError:
        loader = RegistryLoader(registry)
        self._registries[registry] = loader
    self.insert_func_defn(loader.new_registrations('functions'))
    self._insert_getattr_defn(loader.new_registrations('getattrs'))
    self._insert_setattr_defn(loader.new_registrations('setattrs'))
    self._insert_cast_defn(loader.new_registrations('casts'))
    self._insert_get_constant_defn(loader.new_registrations('constants'))
