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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 retrieve_styles(self, asset_url_path):
 """ Get style URLs from the source HTML page and specified cached asset base URL. """

        if not asset_url_path.endswith('/'):
            asset_url_path += '/'
        self.style_urls.extend(self._get_style_urls(asset_url_path))