def _uptime_plan9():
<EOL>try:<EOL><INDENT>f = open('<STR_LIT>', '<STR_LIT:r>')<EOL>s, ns, ct, cf = f.read().split()<EOL>f.close()<EOL>return float(ct) / float(cf)<EOL><DEDENT>except (IOError, ValueError):<EOL><INDENT>return None<EOL><DEDENT>
Returns uptime in seconds or None, on Plan 9.