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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 admin_url(obj):
 """ Returns the admin URL of the object. No permissions checking is involved, so use with caution to avoid exposing the link to unauthorised users. Example:: {{ foo_obj|admin_url }} renders as:: /admin/foo/123 :param obj: A Django model instance. :return: the admin URL of the object """

    if hasattr(obj, 'get_admin_url'):
        return mark_safe(obj.get_admin_url())
    return mark_safe(admin_url_fn(obj))