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: search_queries_common_terms.go
    path of file: ./repos/scan4all/vendor/github.com/olivere/elastic
    
    the code of the file until where you have to start completion: // Copyright 2012-present Oliver Eilhard. All rights reserved.
// Use of this source code is governed by a MIT-license.
// See http://olivere.mit-license.org/license.txt for details.

package elastic

// CommonTermsQuery is a modern alternative to stopwords
// which improves the precision and recall of search results
// (by taking stopwords into account), without sacrificing performance.
// For more details, see:
// https://www.elastic.co/guide/en/elasticsearch/reference/6.8/query-dsl-common-terms-query.h
    
func (q *CommonTermsQuery) Source() (interface{}, error) {
	//  {
	//    "common": {
	//      "body": {
	//        "query":            "this is bonsai cool",
	//        "cutoff_frequency": 0.001
	//      }
	//    }
	//  }
	source := make(map[string]interface{})
	body := make(map[string]interface{})
	query := make(map[string]interface{})

	source["common"] = body
	body[q.name] = query
	query["query"] = q.text

	if q.cutoffFreq != nil {
		query["cutoff_frequency"] = *q.cutoffFreq
	}
	if q.highFreq != nil {
		query["high_freq"] = *q.highFreq
	}
	if q.highFreqOp != "" {
		query["high_freq_operator"] = q.highFreqOp
	}
	if q.lowFreq != nil {
		query["low_freq"] = *q.lowFreq
	}
	if q.lowFreqOp != "" {
		query["low_freq_operator"] = q.lowFreqOp
	}
	if q.lowFreqMinimumShouldMatch != "" || q.highFreqMinimumShouldMatch != "" {
		mm := make(map[string]interface{})
		if q.lowFreqMinimumShouldMatch != "" {
			mm["low_freq"] = q.lowFreqMinimumShouldMatch
		}
		if q.highFreqMinimumShouldMatch != "" {
			mm["high_freq"] = q.highFreqMinimumShouldMatch
		}
		query["minimum_should_match"] = mm
	}
	if q.analyzer != "" {
		query["analyzer"] = q.analyzer
	}
	if q.boost != nil {
		query["boost"] = *q.boost
	}
	if q.queryName != "" {
		query["_name"] = q.queryName
	}

	return source, nil
}