You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: assignment_mutator.go
    path of file: ./repos/aresdb/controller/mutators/etcd
    
    the code of the file until where you have to start completion: //  Copyright (c) 2017-2018 Uber Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, softwa
    
func (j *ingestionAssignmentMutatorImpl) DeleteIngestionAssignment(namespace, name string) error {
	entityList, entityListVersion, err := readEntityList(j.etcdStore, utils.JobAssignmentsListKey(namespace))
	if err != nil {
		return err
	}

	entityList, found := deleteEntity(entityList, name)
	if !found {
		return common.ErrIngestionAssignmentDoesNotExist
	}
	var entityConfig pb.EntityConfig
	configVersion, err := readValue(j.etcdStore, utils.JobAssignmentsKey(namespace, name), &entityConfig)
	if common.IsNonExist(err) || (err == nil && entityConfig.Tomstoned) {
		return common.ErrIngestionAssignmentDoesNotExist
	} else if err != nil {
		return err
	}

	entityConfig.Tomstoned = true
	return kvstore.NewTransaction().
		AddKeyValue(utils.JobAssignmentsListKey(namespace), entityListVersion, &entityList).
		AddKeyValue(utils.JobAssignmentsKey(namespace, name), configVersion, &entityConfig).
		WriteTo(j.etcdStore)
}