记下WSGIApplication

  """Wraps a set of webapp RequestHandlers in a WSGI-compatible application.

  To use this class, pass a list of (URI regular expression, RequestHandler)
  pairs to the constructor, and pass the class instance to a WSGI handler.
  See the example in the module comments for details.

  The URL mapping is first-match based on the list ordering.
  """

看意思是说：对一些符合WSGI标准的请求处理句柄进行包装。要使用这个类，将一个列表的统一资源定位符，请求处理句柄的二元组传递到它的构造器中，然后将这个类实例传到一个WSGI处理句柄中。其中URL将按照顺序 找到第一个匹配的。