code: def AddFilters(self, filters):
      
      for filt in filters.split(','):
        clean_filt = filt.strip()
        if clean_filt:
          self.filters.append(clean_filt)
      for filt in self.filters:
        if not (filt.startswith('+') or filt.startswith('-')):
          raise ValueError('Every filter in --filters must start with + or -'
                           ' (%s does not)' % filt)
docs: Adds more filters to the existing list of error-message filters.