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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(app, pagename, templatename, context, doctree):
 """Add the slides link to the HTML context."""


    # we can only show the slidelink if we can resolve the filename
    context['show_slidelink'] = (
        app.config.slide_link_html_to_slides and
        hasattr(app.builder, 'get_outfilename')
    )

    if context['show_slidelink']:
        context['slide_path'] = slide_path(app.builder, pagename)