ableValue.init))   let base = DefaultedMutableRangeReplaceableBidirectionalCollection(elements: baseElements)   let startIndex = base.index(     base.startIndex,     offsetBy: numericCast(prefix.count))   let endIndex = base.index(     base.startIndex,     offsetBy: numericCast(prefix.count + elements.count))   return MutableRangeReplaceableBidirectionalSlice(     base: base,     bounds: startIndex..<endIndex) }  