Python Implementation issue of Small Strain Linear Viscoelasticity from "Mechanics of Solid Polymers

Dear All,

This is relevant to the Book published by Jorgen " Mechanics of Solid Polymers". On page 330 there is a python code to draw stress - strain diagram for small strain linear viscoelasticity.

but as the book mentioned, I cannot get the graph as mentioned in the book. I implement this python code in Anaconda platform - Spyder version 3.7.

I tried various ways to obtain this but could not do it.

I included the code exactly as it is included in the book

Could you please someone help me to resolve this.

Mr Jorgen, Can you please help me as this is in the book.

Thanks 

BR,

Aravinda Abeygunawardane