code: def template(self, name):
          
          self.plain, self.html = self._find_tpls(name)
          if not self.plain:
              self.plain = self._find_tpl(name)
          try:
              self.send = self._sendtpl
              yield
          finally:
              self.plain, self.html = None, None
              self.send = self._send
docs: Set an active template to use with our Postman.
  
          This changes the call signature of send.
  
          Arguments:
          - `name`: str
  
          Return: None
          Exceptions: None