code: def write_bel_annotation(self, file: TextIO) -> None:
          
          if not self.is_populated():
              self.populate()
  
          values = self._get_namespace_name_to_encoding(desc='writing names')
  
          write_annotation(
              keyword=self._get_namespace_keyword(),
              citation_name=self._get_namespace_name(),
              description='',
              values=values,
              file=file,
          )
docs: Write as a BEL annotation file.