docs: def execute(cmd):
      """ execute command, return rc and output string.
      The cmd argument can be a string or a list composed of
      the command name and each of its argument.
      eg, ['/usr/bin/cp', '-r', 'src', 'dst'] """
  
      # Parse cmd string to a list
      if not isinstance(cmd, list):
          cmd = shlex.split(cmd)
      # Execute command
      rc = 0
      output = ""
      try:
          output = subprocess.check_output(cmd, close_fds=True,
                                           stderr=subprocess.STDOUT)
      except subprocess.CalledProcessError as err:
          rc = err.returncode
          output = err.output
      except Exception as err:
          err_msg = ('Command "%s" Error: %s' % (' '.join(cmd), str(err)))
          raise exception.SDKInternalError(msg=err_msg)
  
      output = bytes.decode(output)
      return (rc, output)