private org.nd4j.shade.protobuf.RepeatedFieldBuilderV3<
          org.nd4j.ir.MapperNamespace.MapperDeclaration, org.nd4j.ir.MapperNamespace.MapperDeclaration.Builder, org.nd4j.ir.MapperNamespace.MapperDeclarationOrBuilder> 
          getMappingsFieldBuilder() {
        if (mappingsBuilder_ == null) {
          mappingsBuilder_ = new org.nd4j.shade.protobuf.RepeatedFieldBuilderV3<