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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 pages(self):
 """ This is a list of HarPage objects, each of which represents a page from the HAR file. """

        # Start with a page object for unknown entries if the HAR data has
        # any entries with no page ID
        pages = []
        if any('pageref' not in entry for entry in self.har_data['entries']):
            pages.append(HarPage('unknown', har_parser=self))
        for har_page in self.har_data['pages']:
            page = HarPage(har_page['id'], har_parser=self)
            pages.append(page)

        return pages