Params given to exec_cmd should satisfy required params.

        :params: kwargs
        :raises: MissingRequiredCommandParameter

def _check_command_parameters(self, **kwargs):
        """Params given to exec_cmd should satisfy required params.

        :params: kwargs
        :raises: MissingRequiredCommandParameter
        """
        rset = self._meta_data['required_command_parameters']
        check = _missing_required_parameters(rset, **kwargs)
        if check:
            error_message = 'Missing required params: %s' % check
            raise MissingRequiredCommandParameter(error_message)