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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 get_url_mappings(self, rule_filter=None):
 """ Returns all werkzeug rules """

        rule_filter = rule_filter or (lambda rule: True)
        app_rules = [
            rule for rule in current_app.url_map.iter_rules()
            if rule_filter(rule)
        ]
        return app_rules