`Shader' does not contain a definition for `Find' Please Help

I have imported post processing stack and suddenly this error shows up, i have searched everywhere aand got no where close.

unity Suddenly Throwing Shader.find and shader.propertytoid Definition not found error.

im Using Unity3d 2018.2 . Please help with this

Thank you in advace

Are you downloading the Post Processing Stack from the Asset Store or from Github? Because the one on the Asset Store is way out of day compared to the one on Github.