return none();
      case 1:
        return is(sequence.charAt(0));
      case 2:
        return isEither(sequence.charAt(0), sequence.charAt(1));
      default:
        // TODO(lowasser): is it potentially worth just going ahead and building a precomputed
        // matcher?
        return new AnyOf(sequence);
    }
  }

  /**
   * Returns a {@code char} matcher that matches any BMP character not present in the given

        return none();
      case 1:
        return is(sequence.charAt(0));
      case 2:
        return isEither(sequence.charAt(0), sequence.charAt(1));
      default:
        // TODO(lowasser): is it potentially worth just going ahead and building a precomputed
        // matcher?
        return new AnyOf(sequence);
    }
  }

  /**
   * Returns a {@code char} matcher that matches any BMP character not present in the given

      return collectTypes(ImmutableList.of(type));
    }

    ImmutableList<K> collectTypes(Iterable<? extends K> types) {
      // type -> order number. 1 for Object, 2 for anything directly below, so on so forth.
      Map<K, Integer> map = Maps.newHashMap();
      for (K type : types) {
        collectTypes(type, map);
      }
      return sortKeysByValue(map, Ordering.natural().reverse());
    }

		HTTPStatusCode: http.StatusBadRequest,
	},

	// Generic Invalid-Request error. Should be used for response errors only for unlikely
	// corner case errors for which introducing new APIErrorCode is not worth it. LogIf()
	// should be used to log the error at the source of the error for debugging purposes.
	ErrInvalidRequest: {
		Code:           "InvalidRequest",
		Description:    "Invalid Request",