code: function UniqueConstraintError(message, innerMessage, model) {
      UniqueConstraintError.super_.bind(this)('EUNQ', message || 'A unique constraint violated', innerMessage, model);
  }
docs: Thrown when a unique constraint is being violated
  @param {string=} message - The error message
  @param {string=} innerMessage - The error inner message
  @param {string=} model - The target model
  @constructor
  @extends DataError