code: function PropertyTemplate(name, required, nullable, template){
    this.name = name;
    this.required = required;
    this.nullable = nullable;
    this.template = template;
  }
docs: Creates a PropertyTemplate.
  
  @param {object} name - property name.
  @param {boolean} required - whether this property is required.
  @param {boolean} nullable - whether this property value can be null.
  @param {object} template - property value template.
  @constructor