<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def detect_old(data):
    "Check for a config file with old schema"
    if not data:
        return False
    ok, errors, warnings = _schema.validate(_OLD_SCHEMA, data)
    return ok and not (errors or warnings)