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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_pkg_list(self):
 """Fetch and cache master list of package names from PYPI"""

        self.logger.debug("DEBUG: Fetching package name list from PyPI")
        package_list = self.list_packages()
        cPickle.dump(package_list, open(self.pkg_cache_file, "w"))
        self.pkg_list = package_list