code: def set_cookie(self, key, value='', max_age=None, expires=None,
                     path='/', domain=None, secure=None, httponly=False):
          
          self.headers.add('Set-Cookie', dump_cookie(key, value, max_age,
                           expires, path, domain, secure, httponly,
                           self.charset))
docs: Sets a cookie. The parameters are the same as in the cookie `Morsel`
          object in the Python standard library but it accepts unicode data, too.
  
          :param key: the key (name) of the cookie to be set.
          :param value: the value of the cookie.
          :param max_age: should be a number of seconds, or `None` (default) if
                          the cookie should last only as long as the client's
                          browser session.
          :param expires: should be a `datetime` object or UNIX timestamp.
          :param domain: if you want to set a cross-domain cookie.  For example,
                         ``domain=".example.com"`` will set a cookie that is
                         readable by the domain ``www.example.com``,
                         ``foo.example.com`` etc.  Otherwise, a cookie will only
                         be readable by the domain that set it.
          :param path: limits the cookie to a given path, per default it will
                       span the whole domain.