def get_connection_string(connection=None):
if not connection:<EOL><INDENT>config = configparser.ConfigParser()<EOL>cfp = defaults.config_file_path<EOL>if os.path.exists(cfp):<EOL><INDENT>log.info('<STR_LIT>', cfp)<EOL>config.read(cfp)<EOL>connection = config['<STR_LIT>']['<STR_LIT>']<EOL>log.info('<STR_LIT>', cfp, connection)<EOL><DEDENT>else:<EOL><INDENT>with open(cfp, '<STR_LIT:w>') as config_file:<EOL><INDENT>connection = defaults.sqlalchemy_connection_string_default<EOL>config['<STR_LIT>'] = {'<STR_LIT>': connection}<EOL>config.write(config_file)<EOL>log.info('<STR_LIT>', cfp)<EOL><DEDENT><DEDENT><DEDENT>return connection<EOL>
return SQLAlchemy connection string if it is set

    :param connection: get the SQLAlchemy connection string #TODO
    :rtype: str