Issue when linking in Xcode 9.4

[AbhishekChourasia16690]

Hello Sir,

Thank you for sharing this demo on Github.

When I added these in my project, the code compiles but when it starts linking then it throws error as below:
Undefined symbols for architecture arm64:
"OBJC_CLASS$_TAGContainerOpener", referenced from:
objc-class-ref in AppDelegate.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I added below code in AppDelegate.swift file:
TAGContainerOpener.openContainer(withId: "GTM-PT3L9Z", // change the container ID "GTM-PT3L9Z" to yours
tagManager: GTM, openType: kTAGOpenTypePreferFresh,
timeout: nil,
notifier: self)

Could you please tell me why I get this linking error.
Waiting for your reply.

Thanks.

(Note: I removed .a file and checked still not working)