How to use the svglib.svglib.ElementWrapper function in svglib

def parent(self):
        par = self.object.getparent()
        return ElementWrapper(par) if par is not None else None

def apply_rules(self, rules):
        matches = rules.match(self)
        for match in matches:
            attr_dict = match[3][1]
            for attr, val in attr_dict.items():
                if attr not in self.object.attrib:
                    try:
                        self.object.attrib[attr] = val
                    except ValueError:
                        pass
        # Set marker on the node to not apply rules more than once
        self.object.set('__rules_applied', '1')


class NodeTracker(ElementWrapper):
    """An object wrapper keeping track of arguments to certain method calls.

    Instances wrap an object and store all arguments to one special
    method, getAttribute(name), in a list of unique elements, usedAttrs.
    """

    def __init__(self, obj):
        super().__init__(obj)
        self.usedAttrs = []

    def __repr__(self):
        return '' % self.object

    def getAttribute(self, name):
        # add argument to the history, if not already present
        if name not in self.usedAttrs: