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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def annotate_rule_violation(self, rule: ValidationRule) -> None: """ Takes note of a rule validation failure by collecting its error message. :param rule: Rule that failed validation. :type rule: ValidationRule :return: None """

        if self.errors.get(rule.label) is None:
            self.errors[rule.label] = []
        self.errors[rule.label].append(rule.get_error_message())