code: func (c *Cloud) getInstanceByID(instanceID string) (*ec2.Instance, error) {
  	instances, err := c.getInstancesByIDs([]*string{&instanceID})
  	if err != nil {
  		return nil, err
  	}
  
  	if len(instances) == 0 {
  		return nil, cloudprovider.ErrInstanceNotFound
  	}
  	if len(instances) > 1 {
  		return nil, fmt.Errorf("multiple instances found for instance: %s", instanceID)
  	}
  
  	return instances[instanceID], nil
  }
docs: // Returns the instance with the specified ID