how to install PresentationFramework.dll in windows 10

I've been using Visual Studio 2019 and .Net core 3.0 preview 5. I have tried to make unit tests but i couldn't because i have an exceptionMessage:

System.BadImageFormatException : Could not load file or assembly 'PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Reference assemblies should not be loaded for execution.  They can only be loaded in the Reflection-only loader context. (0x80131058)
---- System.BadImageFormatException : Cannot load a reference assembly for execution.

I tried to find something about this on the internet, but i found only that i have to change one file in the GAC. I have to change PresentationFramework.dll 3.0.0.0 to 4.0.0.0 version. I don't know how so I'm here to ask you, how to change version.