removeAttribute(attributeName) {
    if (this.doc !== null) {
      transact(this.doc, transaction => {
        typeMapDelete(transaction, this, attributeName);
      });
    } else {
      /** @type {Map<string,any>} */
      this._prelimAttrs.delete(attributeName);
    }
  }
Removes an attribute from this YXmlElement.

@param {String} attributeName The attribute name that is to be removed.

@public