'Deletes a specified DBParameterGroup. The DBParameterGroup
cannot be associated with any RDS instances to be deleted.
The specified DB parameter group cannot be associated with any
DB instances.
:type db_parameter_group_name: string
:param db_parameter_group_name:
The name of the DB parameter group.
Constraints:
+ Must be the name of an existing DB parameter group
+ You cannot delete a default DB parameter group
+ Cannot be associated with any DB instances'

def delete_db_parameter_group(self, db_parameter_group_name):

    params = {'DBParameterGroupName': db_parameter_group_name}
    return self._make_request(action='DeleteDBParameterGroup', verb='POST', path='/', params=params)
