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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 merge(self, other, merge_body=True):
 """ Default merge method. Args: other: another MujocoXML instance raises XML error if @other is not a MujocoXML instance. merges <worldbody/>, <actuator/> and <asset/> of @other into @self merge_body: True if merging child bodies of @other. Defaults to True. """

        if not isinstance(other, MujocoXML):
            raise XMLError("{} is not a MujocoXML instance.".format(type(other)))
        if merge_body:
            for body in other.worldbody:
                self.worldbody.append(body)
        self.merge_asset(other)
        for one_actuator in other.actuator:
            self.actuator.append(one_actuator)
        for one_equality in other.equality:
            self.equality.append(one_equality)
        for one_contact in other.contact:
            self.contact.append(one_contact)
        for one_default in other.default:
            self.default.append(one_default)