A notice to appear has the same effect as a subpoena, which is the equivalent of a court order. (Code Civ. Proc., ?? 1987, subds. (a),(b).) Indeed, a subpoena is a writ or order directed to a person and requiring the person's attendance at a particular time and place to testify as a witness. (Code Civ. Proc., ?? 1985, subd. (a).) Thus, Wayne violated a court order in failing to appear at trial a