code: public K findKey (int value) {
  		K[] keyTable = this.keyTable;
  		int[] valueTable = this.valueTable;
  		for (int i = capacity + stashSize; i-- > 0;)
  			if (keyTable[i] != null && valueTable[i] == value) return keyTable[i];
  		return null;
  	}
docs: Returns the key for the specified value, or null if it is not in the map. Note this traverses the entire map and compares
  every value, which may be an expensive operation.