code: func GetSpongeFunc(spongeFunc []SpongeFunction, defaultSpongeFuncCreator ...SpongeFunctionCreator) SpongeFunction {
  	if len(spongeFunc) > 0 {
  		return spongeFunc[0]
  	}
  	if len(defaultSpongeFuncCreator) > 0 {
  		return defaultSpongeFuncCreator[0]()
  	}
  	panic("No sponge function given")
  }
docs: // GetSpongeFunc checks if a hash function was given, otherwise uses defaultSpongeFuncCreator. Panics if none given.