code: def execute(cmd):
    ''' Call cmd and return output. return None if any exception occurs '''
    try:
      return safely_decode(check_output(cmd))
    except Exception as e:
      logger.warn(u'Couldnt execute cmd: %s.\nReason: %s' % (cmd, e))
      return Nonf execute(cmd):
    ''' Call cmd and return output. return None if any exception occurs '''
    try:
      return safely_decode(check_output(cmd))
    except Exception as e:
      logger.warn(u'Couldnt execute cmd: %s.\nReason: %s' % (cmd, e))
      return None
docs: Call cmd and return output. return None if any exception occurs