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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 add_link_header(response, links):
 """Add a Link HTTP header to a REST response. :param response: REST response instance :param links: Dictionary of links """

    if links is not None:
        response.headers.extend({
            'Link': ', '.join([
                '<{0}>; rel="{1}"'.format(l, r) for r, l in links.items()])
        })