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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 if_relationship(parser, token):
 """ Determine if a certain type of relationship exists between two users. The ``status`` parameter must be a slug matching either the from_slug, to_slug or symmetrical_slug of a RelationshipStatus. Example:: {% if_relationship from_user to_user "friends" %} Here are pictures of me drinking alcohol {% else %} Sorry coworkers {% endif_relationship %} {% if_relationship from_user to_user "blocking" %} damn seo experts {% endif_relationship %} """

    bits = list(token.split_contents())
    if len(bits) != 4:
        raise TemplateSyntaxError("%r takes 3 arguments:\n%s" % (bits[0], if_relationship.__doc__))
    end_tag = 'end' + bits[0]
    nodelist_true = parser.parse(('else', end_tag))
    token = parser.next_token()
    if token.contents == 'else':
        nodelist_false = parser.parse((end_tag,))
        parser.delete_first_token()
    else:
        nodelist_false = template.NodeList()
    return IfRelationshipNode(nodelist_true, nodelist_false, *bits[1:])