code: private static boolean contains(Object[] arr, Object member) {
          for (Object mem : arr) {
              if (Objects.equals(mem, member)) {
                  return true;
              }
          }
          return false;
      }
docs: Tests array membership.
  
  @param arr the array.
  @param member an object.
  @return <code>true</code> if the provided object is a member of the
  provided array, or <code>false</code> if not.