def __get__(self, instance, owner):
        if instance is None:
            return self
        value = Option.__get__(self, instance, owner)
        for impl in self.xtnpt.extensions(instance):
            if impl.__class__.__name__ == value:
                return impl
        raise ConfigurationError(
            tag_("Cannot find an implementation of the %(interface)s "
                 "interface named %(implementation)s. Please check "
                 "that the Component is enabled or update the option "
                 "%(option)s in trac.ini.",
                 interface=tag.code(self.xtnpt.interface.__name__),
                 implementation=tag.code(value),
                 option=tag.code("[%s] %s" % (self.section, self.name))))
dataset/ETHPy150Open edgewall/trac/trac/config.py/ExtensionOption.__get__/original