code: def parse_stderr(self, filelike):
          
          marker_error = 'ERROR,'
          marker_warning = 'WARNING,'
  
          messages = {'errors': [], 'warnings': []}
  
          for line in filelike.readlines():
              if marker_error in line:
                  messages['errors'].append(line.split(marker_error)[-1].strip())
              if marker_warning in line:
                  messages['warnings'].append(line.split(marker_warning)[-1].strip())
  
          if self.node.get_option('attach_messages'):
              self.out('messages', Dict(dict=messages))
  
          for error in messages['errors']:
              if 'unknown option' in error:
                  return self.exit_codes.ERROR_INVALID_COMMAND_LINE_OPTION
  
          return
docs: Parse the content written by the script to standard err.
  
          :param filelike: filelike object of stderr
          :returns: an exit code in case of an error, None otherwise