code: func (e *Adaptor) GetConnection(address int, bus int) (connection i2c.Connection, err error) {
  	if (bus < 0) || (bus > 2) {
  		return nil, fmt.Errorf("Bus number %d out of range", bus)
  	}
  	if e.i2cBuses[bus] == nil {
  		e.i2cBuses[bus], err = sysfs.NewI2cDevice(fmt.Sprintf("/dev/i2c-%d", bus))
  	}
  	return i2c.NewConnection(e.i2cBuses[bus], address), err
  }
docs: // GetConnection returns an i2c connection to a device on a specified bus.
  // Valid bus number is [0..2] which corresponds to /dev/i2c-0 through /dev/i2c-2.