code: def make_path_relative(path):
      
      if os.path.isabs(path):
          drive_s,path = os.path.splitdrive(path)
  
          import re
          if not drive_s:
              path=re.compile("/*(.*)").findall(path)[0]
          else:
              path=path[1:]
  
      assert( not os.path.isabs( path ) ), path
      return path
docs: makes an absolute path name to a relative pathname.