Hello, I am trying to integrate Firebase Analytics with my swift app and I have followed the instructions to do this integration on the official Firebase page and everything seems to work fine until I make use of the Analytics logEvent statement and it throws the following compile error: Undefined symbols for architecture x86_64: "_OBJCCLASS $ _ FIRApp", referenced from: objc-class-ref in AppDelegate.o "_OBJCCLASS $ _ FIRAnalytics", referenced from: objc-class-ref in FirebaseUtils.o