def check(self, instance, format):

        if format not in self.checkers:
            return

        func, raises = self.checkers[format]
        result, cause = None, None
        try:
            result = func(instance)
        except raises as e:
            cause = e
        if not result:
            raise FormatError(
                "%r is not a %r" % (instance, format), cause=cause,
            )
Check whether the instance conforms to the given format.
dataset/ETHPy150Open Julian/jsonschema/jsonschema/_format.py/FormatChecker.check