code: func (b *UpdateService) body() (interface{}, error) {
  	source := make(map[string]interface{})
  
  	if b.script != nil {
  		src, err := b.script.Source()
  		if err != nil {
  			return nil, err
  		}
  		source["script"] = src
  	}
  
  	if b.scriptedUpsert != nil {
  		source["scripted_upsert"] = *b.scriptedUpsert
  	}
  
  	if b.upsert != nil {
  		source["upsert"] = b.upsert
  	}
  
  	if b.doc != nil {
  		source["doc"] = b.doc
  	}
  	if b.docAsUpsert != nil {
  		source["doc_as_upsert"] = *b.docAsUpsert
  	}
  	if b.detectNoop != nil {
  		source["detect_noop"] = *b.detectNoop
  	}
  	if b.fsc != nil {
  		src, err := b.fsc.Source()
  		if err != nil {
  			return nil, err
  		}
  		source["_source"] = src
  	}
  
  	return source, nil
  }
docs: // body returns the body part of the document request.