def _num_cpus_darwin():
 p = subprocess.Popen(['sysctl', '-n', 'hw.ncpu'], stdout=subprocess.PIPE)
 return p.stdout.read()

def _num_cpus_darwin ( ) : p = subprocess . Popen ( [ 'sysctl' , '-n' , 'hw.ncpu' ] , stdout = subprocess . PIPE ) return p . stdout . read ( )
return the number of active cpus on a darwin system .