<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def system_call(command):
 """Run a command and return stdout. Would be better to use subprocess.check_output, but this works on 2.6, which is still the system Python on CentOS 7."""

  p = subprocess.Popen([command], stdout=subprocess.PIPE, shell=True)
  return p.stdout.read()