code: @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;
      }
docs: Add a method annotation. If this is the first method annotation added, it
  becomes the primary method annotation. If the method has source line
  information, then a SourceLineAnnotation is added to the method.
  
  @param methodGen
  the MethodGen object for the method
  @param sourceFile
  source file method is defined in
  @return this object