```go
// hashes the key returning an integer.
func sipHashMod(key string, cardinality int, id [16]byte) int {
        if cardinality <= 0 {
                return -1
        }
        sip := siphash.New(id[:])
        sip.Write([]byte(key))
        return int(sip.Sum64() % uint64(cardinality))
}
```

// in the slices returned.
func hashOrder(key string, cardinality int) []int {
	if cardinality <= 0 {
		// Returns an empty int slice for cardinality < 0.
		return nil
	}

	nums := make([]int, cardinality)
	keyCrc := crc32.Checksum([]byte(key), crc32.IEEETable)

	start := int(keyCrc % uint32(cardinality))
	for i := 1; i <= cardinality; i++ {
		nums[i-1] = 1 + ((start + i) % cardinality)
	}
	return nums
}

var (

     */
    @Override
    public Iterator<E> iterator() {
        return map.keySet().iterator();
    }

    /**
     * Returns the number of elements in this set (its cardinality).
     *
     * @return the number of elements in this set (its cardinality).
     */
    @Override
    public int size() {
        return map.size();
    }

    /**
     * Returns true if this set contains no elements.
     *

      result += System.identityHashCode(matcher.collapseFrom(teststring, ' '));
    }
    return result;
  }

  private static String allMatchingChars(BitSet bitSet) {
    final char[] result = new char[bitSet.cardinality()];
    for (int j = 0, c = bitSet.nextSetBit(0); j < result.length; ++j) {
      result[j] = (char) c;
      c = bitSet.nextSetBit(c + 1);
    }
    return new String(result);
  }

      result += System.identityHashCode(matcher.collapseFrom(teststring, ' '));
    }
    return result;
  }

  private static String allMatchingChars(BitSet bitSet) {
    final char[] result = new char[bitSet.cardinality()];
    for (int j = 0, c = bitSet.nextSetBit(0); j < result.length; ++j) {
      result[j] = (char) c;
      c = bitSet.nextSetBit(c + 1);
    }
    return new String(result);
  }

   */
  protected final void expectContents(E... elements) {
    expectContents(asList(elements));
  }

  /**
   * Asserts that the collection under test contains exactly the given elements, respecting
   * cardinality but not order. Subclasses may override this method to provide stronger assertions,
   * e.g., to check ordering in lists, but realize that <strong>unless a test extends {@link