def set_cookie(self, cookie_string):
        """Request to set a cookie.

        Note that it is NOT necessary to call this method under ordinary
        circumstances: cookie handling is normally entirely automatic.  The
        intended use case is rather to simulate the setting of a cookie by
        client script in a web page (e.g. JavaScript).  In that case, use of
        this method is necessary because mechanize currently does not support
        JavaScript, VBScript, etc.

        The cookie is added in the same way as if it had arrived with the
        current response, as a result of the current request.  This means that,
        for example, if it is not appropriate to set the cookie based on the
        current request, no cookie will be set.

        The cookie will be returned automatically with subsequent responses
        made by the Browser instance whenever that's appropriate.

        cookie_string should be a valid value of the Set-Cookie header.

        For example:

        browser.set_cookie(
            "sid=abcdef; expires=Wednesday, 09-Nov-06 23:12:40 GMT")

        Currently, this method does not allow for adding RFC 2986 cookies.
        This limitation will be lifted if anybody requests it.

        """
        if self._response is None:
            raise BrowserStateError("not viewing any document")
        if ["http", "https"] not in self.request.get_type():
            raise BrowserStateError("can't set cookie for non-HTTP/HTTPS "
                                    "transactions")
        cookiejar = self._ua_handlers["_cookies"].cookiejar
        response = self.response()  # copy
        headers = response.info()
        headers["Set-cookie"] = cookie_string
        cookiejar.extract_cookies(response, self.request)
dataset/ETHPy150Open deanhiller/databus/webapp/play1.3.x/samples-and-tests/i-am-a-developer/mechanize/_mechanize.py/Browser.set_cookie/swapped operands of `not in`