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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 fetch_releases(self, package_name):
 """Fetch package and index_url for a package_name."""

        package_name = self.source.normalize_package_name(package_name)
        releases = self.source.get_package_versions(package_name)
        releases_with_index_url = [(item, self.index_url) for item in releases]
        return package_name, releases_with_index_url