def _read_file(self):
if not os.path.exists(self.db_path):<EOL><INDENT>return {}<EOL><DEDENT>with open(self.db_path, '<STR_LIT:r>') as f:<EOL><INDENT>content = f.read()<EOL>return json.loads(content)<EOL><DEDENT>
read the db file content
:rtype: dict