'Modify a ParameterGroup for your account.
:type name: string
:param name: The name of the new ParameterGroup
: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'

def modify_parameter_group(self, name, parameters=None):

    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')
