def _is_plugable_7port_hub(node):
  """Check if a node is a Plugable 7-Port Hub
  (Model USB2-HUB7BC)
  The topology of this device is a 4-port hub,
  with another 4-port hub connected on port 4.
  """
  if '1a40:0101' not in node.desc:
    return False
  if not node.HasPort(4):
    return False
  return '1a40:0101' in node.PortToDevice(4).desc