In Sherman v. United States, 356 U.S. 369 (1958), the defense called no witnesses. The Court concluded from the evidence that entrapment was established as a matter of law. In so holding, the Court stated that it was "not choosing between conflicting witnesses, nor judging credibility . . . We reach our conclusion from the undisputed testimony of the prosecution's witnesses." Id. Therefore, the trial judge erred, as a matter of law, when he denied the charge on the ground Brown did not testify, call witnesses, or present any evidence other than through the prosecution witnesses.