docs: def discard(self, s):
          """
          Discard from original file.
          """
  
          lines = s.splitlines(True)
          for line in lines:
              if line[-1] not in '\r\n':
                  if not self.warn:
                      logger.warning(
                          'partial line discard UNSUPPORTED; source map '
                          'generated will not match at the column level'
                      )
                      self.warn = True
              else:
                  # simply increment row
                  self.row += 1