docs: def build(self, builder):
          """
          Build XML by appending to builder
          """
          if self.text is None:
              raise ValueError("Text is not set.")
          params = {}
          if self.sponsor_or_site is not None:
              params['SponsorOrSite'] = self.sponsor_or_site
  
          builder.start("Comment", params)
          builder.data(self.text)
          builder.end("Comment")