code: def loc_info(text, index):
          '''Location of `index` in source code `text`.'''
          if index > len(text):
              raise ValueError('Invalid index.')
          line, last_ln = text.count('\n', 0, index), text.rfind('\n', 0, index)
          col = index - (last_ln + 1)
          return (line, colf loc_info(text, index):
          '''Location of `index` in source code `text`.'''
          if index > len(text):
              raise ValueError('Invalid index.')
          line, last_ln = text.count('\n', 0, index), text.rfind('\n', 0, index)
          col = index - (last_ln + 1)
          return (line, col)
docs: Location of `index` in source code `text`.