code: func UnionUint64Arr(arr [][]uint64) []uint64 {
  	// create a temporary map to hold the contents of the arrays
  	tempMap := make(map[uint64]uint8)
  
  	// write the contents of the arrays as keys to the map. The map values don't matter
  	for idx1 := range arr {
  		for idx2 := range arr[idx1] {
  			tempMap[arr[idx1][idx2]] = 0
  		}
  	}
  
  	// the map keys are now unique instances of all of the array contents
  	tempArray := make([]uint64, 0)
  	for key := range tempMap {
  		tempArray = append(tempArray, key)
  	}
  
  	return tempArray
  }
docs: // UnionUint64Arr finds the union of two arrays using a multidimensional array as inputs
  //
  // Deprecated: use Union instead.