Please help with the sentences below.
Independent Directions (Titile)
In the furor over the lax behavior of directors, even Buffett has received heat.
Recently, Calpers challenged his independence as a board director of Coca-Cola.
In rebuttal, Buffett said that there is no substitute for thinking. There is no magic checklist that is going to tell you in all cases whether a director is independent.
Q1: What is 'Calpers challenged his independence'?
Q2: 'There is no magic checklist that is going to tell you in all cases whether a director is independent"?