Not found Compression FileArchive when importing GG Admob

I met this message when importing GG Admob with System.IO.Compression.FileArchive.

 Assets/Scripts/Compress/ZipFileWithProgress.cs(17,16): error CS1069: The type name 'ZipArchive' could not be found in the namespace 'System.IO.Compression'. This type has been forwarded to assembly 'System.IO.Compression, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' Consider adding a reference to that assembly.

I didn't meet this error before importing GG admob. Please help me, thanks all.