code: public static Predicate<Class<?>> inPackage(final String packageNamePrefix) {
          return clazz -> clazz.getPackage().getName().startsWith(packageNamePrefix);
      }
docs: Create a predicate to check that a type is defined in a given package.
  
  @param packageNamePrefix prefix of the package name
  @return Predicate to check that a type is defined in a given package.