def getUsersWithinRole(self, rolename, filter=None, maxCount=20):
        """
           You can use this operation to conveniently see all the user
           accounts to whom this role has been assigned.
           Inputs:
              rolename - name of the role
              filter - filter to be applied to the resultant user set
              maxCount - maximum number of results to return
           Output:
              JSON Message as dictionary
        """
        uURL = self._url + "/roles/getUsersWithinRole"
        params = {
            "f" : "json",
            "rolename" : rolename,
            "maxCount" : maxCount
        }
        if filter is not None and \
           isinstance(filter, str):
            params['filter'] = filter
        return self._post(url=uURL, param_dict=params,
                             securityHandler=self._securityHandler,
                             proxy_url=self._proxy_url,
                             proxy_port=self._proxy_port)