code: func (b *Adaptor) GetConnection(address int, bus int) (connection i2c.Connection, err error) {
  	b.mutex.Lock()
  	defer b.mutex.Unlock()
  
  	if (bus != 0) && (bus != 2) {
  		return nil, fmt.Errorf("Bus number %d out of range", bus)
  	}
  	if b.i2cBuses[bus] == nil {
  		b.i2cBuses[bus], err = sysfs.NewI2cDevice(fmt.Sprintf("/dev/i2c-%d", bus))
  	}
  	return i2c.NewConnection(b.i2cBuses[bus], address), err
  }
docs: // GetConnection returns a connection to a device on a specified bus.
  // Valid bus number is either 0 or 2 which corresponds to /dev/i2c-0 or /dev/i2c-2.