getEditorNSMethod = (add) => {
  if (add) {
    svgCanvas.getSvgContent().setAttribute('xmlns:se', NS.SE)
  }
  return NS.SE
}
Returns the editor's namespace URL, optionally adding it to the root element.
@function module:elem-get-set.SvgCanvas#getEditorNS
@param {boolean} [add] - Indicates whether or not to add the namespace value
@returns {string} The editor's namespace URL