code: func ByteKeySet(theMap interface{}) Byte {
  	v := reflect.ValueOf(theMap)
  	ret := Byte{}
  
  	for _, keyValue := range v.MapKeys() {
  		ret.Insert(keyValue.Interface().(byte))
  	}
  	return ret
  }
docs: // ByteKeySet creates a Byte from a keys of a map[byte](? extends interface{}).
  // If the value passed in is not actually a map, this will panic.