title: Adding a constant tuple value to a list of tuples
body: <p>I have a list of tuples (each tuple item is a pair of integers) and I would like to add a constant value to each tuple in the list.</p>
  
  <p>For example
  [(x0,y0),(x1,y1),...] -> [(x0+xk,y0+yk),(x1+xk,y1+yk)....] </p>
  
  <p>xk,yk are constants</p>
  
  <p>How do I do this</p>
  
  <p>Thanks</p>