def set_default_proxy(cls, value):
        """
        Default: None (no proxy)

        A string that will be used to tell each request must be sent through this proxy server.
        Use the scheme://hostname:port form.
        If you need to use a proxy, you can configure individual requests with the proxies argument to any request
        method.
        """
        if value is None:
            cls.DEFAULT_PROXY = None
        else:
            scheme, host, port = get_hostname_parameters_from_url(value)
            cls.DEFAULT_PROXY = "%s://%s:%s" % (scheme, host, port)