code: def return_buffer_contents(self, frame, force_unescaped=False):
          
          if not force_unescaped:
              if frame.eval_ctx.volatile:
                  self.writeline('if context.eval_ctx.autoescape:')
                  self.indent()
                  self.writeline('return Markup(concat(%s))' % frame.buffer)
                  self.outdent()
                  self.writeline('else:')
                  self.indent()
                  self.writeline('return concat(%s)' % frame.buffer)
                  self.outdent()
                  return
              elif frame.eval_ctx.autoescape:
                  self.writeline('return Markup(concat(%s))' % frame.buffer)
                  return
          self.writeline('return concat(%s)' % frame.buffer)
docs: Return the buffer contents of the frame.