code: def replace(pretty, old_str, new_str):
      
      out_str = ''
      line_number = 1
      changes = 0
      for line in pretty.splitlines(keepends=True):
          new_line = line.replace(old_str, new_str)
          if line.find(old_str) != -1:
              logging.debug('%s', line_number)
              logging.debug('< %s', line)
              logging.debug('> %s', new_line)
              changes += 1
          out_str += new_line
          line_number += 1
  
      logging.info('Total changes(%s): %s', old_str, changes)
      return out_str
docs: Replace strings giving some info on where
      the replacement was done