function setDefaultStateProxy(el) {
  el.stateProxy = elementStateProxy;
  var textContent = el.getTextContent();
  var textGuide = el.getTextGuideLine();

  if (textContent) {
    textContent.stateProxy = elementStateProxy;
  }

  if (textGuide) {
    textGuide.stateProxy = elementStateProxy;
  }
}
FI
Set hover style (namely "emphasis style") of element.
@param el Should not be `zrender/graphic/Group`.
@param focus 'self' | 'selfInSeries' | 'series'