def load_systemjs_manifest(self):
<EOL>_manifest_name = self.manifest_name<EOL>self.manifest_name = self.systemjs_manifest_name<EOL>bundle_files = self.load_manifest()<EOL>self.manifest_name = _manifest_name<EOL>for file, hashed_file in bundle_files.copy().items():<EOL><INDENT>if not self.exists(file) or not self.exists(hashed_file):<EOL><INDENT>del bundle_files[file]<EOL><DEDENT><DEDENT>return bundle_files<EOL>
Load the existing systemjs manifest and remove any entries that no longer
exist on the storage.