docs: public Method getMethod(Class<?> returnType, String name, Class<?>... paramTypes) {
          final Map<ParamList, Map<Class<?>, Method>> nameMap = methods.get(name);
          if (nameMap == null) {
              return null;
          }
          final Map<Class<?>, Method> paramsMap = nameMap.get(createParamList(paramTypes));
          if (paramsMap == null) {
              return null;
          }
          return paramsMap.get(returnType);
      }