code: private List<ParameterConverter> findConverters(Injector injector) {
          List<Binding<ParameterConverter>> bindingsByType = injector
                  .findBindingsByType(new TypeLiteral<ParameterConverter>() {
                  });
          if (bindingsByType.isEmpty() && injector.getParent() != null) {
              return findConverters(injector.getParent());
          }
          List<ParameterConverter> converters = new ArrayList<>();
          for (Binding<ParameterConverter> binding : bindingsByType) {
              converters.add(binding.getProvider().get());
          }
          return converters;
      }
docs: Finds any {@link ParameterConverter} defined in the given injector and,
  if none found, recurses to its parent.
  
  @param injector
  the Injector
  @return A List of ParameterConverter instances