code: func (r Virtual_Guest) SetPrivateNetworkInterfaceSpeed(newSpeed *int) (resp bool, err error) {
  	params := []interface{}{
  		newSpeed,
  	}
  	err = r.Session.DoRequest("SoftLayer_Virtual_Guest", "setPrivateNetworkInterfaceSpeed", params, &r.Options, &resp)
  	return
  }
docs: // Sets the private network interface speed to the new speed. Speed values can only be 0 (Disconnect), 10, 100, or 1000. The new speed must be equal to or less than the max speed of the interface.
  //
  // It will take less than a minute to update the port speed.