docs: @Nonnull
      public BugInstance addMethod(MethodGen methodGen, String sourceFile) {
          String className = methodGen.getClassName();
          MethodAnnotation methodAnnotation = new MethodAnnotation(className, methodGen.getName(), methodGen.getSignature(),
                  methodGen.isStatic());
          addMethod(methodAnnotation);
          addSourceLinesForMethod(methodAnnotation, SourceLineAnnotation.fromVisitedMethod(methodGen, sourceFile));
          return this;
      }