title: How to add a different data to multiple text files using python?
body: <p>I am student and learning python. I am at a basic level. I am facing an issue to edit the contents of multiple text files. The text files that i have are the annotation files of some images. The images are of multiple shafts in a tray and the annotation files consist of the midpoints and a point along the length of the shaft i.e., (x0,y0) and (x1,y1). I need to insert the angle into these text files using the command math.atan2(y1-y0,x1-x0).</p>
  <p>So can any of you guys help me and guide me</p>
  <p>Thanks</p>