code: func (i *ImportRestriction) isRestrictedDir(dir string) (bool, error) {
  	if under, err := isPathUnder(i.BaseDir, dir); err != nil {
  		return false, err
  	} else if !under {
  		return false, nil
  	}
  
  	for _, ignored := range i.IgnoredSubTrees {
  		if under, err := isPathUnder(ignored, dir); err != nil {
  			return false, err
  		} else if under {
  			return false, nil
  		}
  	}
  
  	return true, nil
  }
docs: // isRestrictedDir determines if the source directory has
  // any restrictions placed on it by this configuration.
  // A path will be restricted if:
  //   - it falls under the base import path
  //   - it does not fall under any of the ignored sub-trees