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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 set_meta(request):
 """ This context processor returns meta informations contained in cached files. If there aren't cache it calculates dictionary to return """

    context_extras = {}
    if not request.is_ajax() and hasattr(request, 'upy_context') and request.upy_context['PAGE']:
        context_extras['PAGE'] = request.upy_context['PAGE']
        context_extras['NODE'] = request.upy_context['NODE']
    return context_extras