code: func (nm DatastoreNamespaceManager) CreateDirectory(ctx context.Context, ds *Datastore, displayName string, policy string) (string, error) {
  
  	req := &types.CreateDirectory{
  		This:        nm.Reference(),
  		Datastore:   ds.Reference(),
  		DisplayName: displayName,
  		Policy:      policy,
  	}
  
  	resp, err := methods.CreateDirectory(ctx, nm.c, req)
  	if err != nil {
  		return "", err
  	}
  
  	return resp.Returnval, nil
  }
docs: // CreateDirectory creates a top-level directory on the given vsan datastore, using
  // the given user display name hint and opaque storage policy.