Undefined symbols for arm64 architecture: "_OBJC_CLASS _ $ _ PayTabCardReaderViewController" referenced by: objc-class-ref in ViewController.o

Question

I get this strange error when importing a library called pay tabs

Undefined symbols for architecture arm64:
"_OBJC_CLASS_$_PayTabCardReaderViewController", referenced from:
  objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

In the build settings

Architecture:

Architecture Standard architectures (armv7, arm64) - $ (ARCHS_STANDARD) Base SDK Recent IOS (8.4)

Built-in Active Architecture Only Debug Yes Release No

Supported IOS platforms Virtual armv7 arm64 architectures

Answer 1

Ahh, isn't Xcode strong?

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( Xcode, MapBox iOS SDK. , " ", Xcode .)

Answer 2

"" → " "? → , .

Answer 3

→ . , .