func (d *Document) SetRef(ref string) *Document {
	d.Ref = ref
	return d
}
SetRef of document
package generator
func (d *Document) SetType(docType string) *Document {
	d.Type = docType
	return d
}
func (d *Document) SetHeader(header *HeaderFooter) *Document {
	d.Header = header
	return d
}
func (d *Document) SetFooter(footer *HeaderFooter) *Document {
	d.Footer = footer
	return d
}