code: def text(self, text, stylename=None):
          
          assert self._containers
          container = self._containers[-1]
          if stylename is not None:
              stylename = self._get_style_name(stylename)
              container.addElement(Span(stylename=stylename, text=text))
          else:
              container.addElement(Span(text=text))
docs: Add text within the current container.