new_contents: from hippy.builtin import wrap,   Optional
  
  
  @wrap(['interp',   str,   str,   str,   Optional(str),   Optional(str)])
  def mail(interp,   to,   topic,   content,
           extra_headers=None,   extra_params=None):
      # XXXX dummy
      return interp.space.w_True
  
subject: add mail function stub