<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def modify_parameter_group(self, name, parameters=None):
 """ Modify a parameter group for your account. :type name: string :param name: The name of the new parameter group :type parameters: list of :class:`boto.rds.parametergroup.Parameter` :param parameters: The new parameters :rtype: :class:`boto.rds.parametergroup.ParameterGroup` :return: The newly created ParameterGroup """

        params = {'DBParameterGroupName': name}
        for i in range(0, len(parameters)):
            parameter = parameters[i]
            parameter.merge(params, i+1)
        return self.get_list('ModifyDBParameterGroup', params,
                             ParameterGroup, verb='POST')