code: func (f *Adaptor) GetConnection(address int, bus int) (connection i2c.Connection, err error) {
  	if bus != 0 {
  		return nil, fmt.Errorf("Invalid bus number %d, only 0 is supported", bus)
  	}
  	err = f.Board.I2cConfig(0)
  	return NewFirmataI2cConnection(f, address), err
  }
docs: // GetConnection returns an i2c connection to a device on a specified bus.
  // Only supports bus number 0