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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_related_entry_admin_url(entry):
 """ Returns admin URL for specified entry instance. :param entry: the entry instance. :return: str. """

    namespaces = {
        Document:   'wagtaildocs:edit',
        Link:       'wagtaillinks:edit',
        Page:       'wagtailadmin_pages:edit',
    }

    for cls, url in namespaces.iteritems():
        if issubclass(entry.content_type.model_class(), cls):
            return urlresolvers.reverse(url, args=(entry.object_id,))

    return ''