def getRolesForUser(self, username, filter=None, maxCount=None):
        """
           This operation returns a list of role names that have been
           assigned to a particular user account.
           Inputs:
              username - name of the user for whom the returned roles
              filter - filter to be applied to the resultant role set.
              maxCount - maximum number of results to return for this query
        """
        uURL = self._url + "/roles/getRolesForUser"
        params = {
            "f" : "json",
            "username" : username
        }
        if filter is not None:
            params['filter'] = filter

        if maxCount is not None:
            params['maxCount'] = maxCount
        return self._post(url=uURL, param_dict=params,
                             securityHandler=self._securityHandler,
                             proxy_url=self._proxy_url,
                             proxy_port=self._proxy_port)