<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def drop_privileges ():
 """Make sure to drop root privileges on POSIX systems."""

    if os.name != 'posix':
        return
    if os.geteuid() == 0:
        log.warn(LOG_CHECK, _("Running as root user; "
                       "dropping privileges by changing user to nobody."))
        import pwd
        os.seteuid(pwd.getpwnam('nobody')[3])