How to use the dugite.GitError.DefaultBranchDeletionFailed function in dugite

case DugiteError.RemoteDisconnection:
      return 'The remote disconnected. Check your Internet connection and try again.'
    case DugiteError.HostDown:
      return 'The host is down. Check your Internet connection and try again.'
    case DugiteError.RebaseConflicts:
      return 'We found some conflicts while trying to rebase. Please resolve the conflicts before continuing.'
    case DugiteError.MergeConflicts:
      return 'We found some conflicts while trying to merge. Please resolve the conflicts and commit the changes.'
    case DugiteError.HTTPSRepositoryNotFound:
    case DugiteError.SSHRepositoryNotFound:
      return 'The repository does not seem to exist anymore. You may not have access, or it may have been deleted or renamed.'
    case DugiteError.PushNotFastForward:
      return 'The repository has been updated since you last pulled. Try pulling before pushing.'
    case DugiteError.BranchDeletionFailed:
      return 'Could not delete the branch. It was probably already deleted.'
    case DugiteError.DefaultBranchDeletionFailed:
      return `The branch is the repository's default branch and cannot be deleted.`
    case DugiteError.RevertConflicts:
      return 'To finish reverting, please merge and commit the changes.'
    case DugiteError.EmptyRebasePatch:
      return 'There aren’t any changes left to apply.'
    case DugiteError.NoMatchingRemoteBranch:
      return 'There aren’t any remote branches that match the current branch.'
    case DugiteError.NothingToCommit:
      return 'There are no changes to commit.'
    case DugiteError.NoSubmoduleMapping:
      return 'A submodule was removed from .gitmodules, but the folder still exists in the repository. Delete the folder, commit the change, then try again.'
    case DugiteError.SubmoduleRepositoryDoesNotExist:
      return 'A submodule points to a location which does not exist.'
    case DugiteError.InvalidSubmoduleSHA:
      return 'A submodule points to a commit which does not exist.'
    case DugiteError.LocalPermissionDenied: