code: func (d *DeferredDiscoveryRESTMapper) ResourceSingularizer(resource string) (singular string, err error) {
  	del, err := d.getDelegate()
  	if err != nil {
  		return resource, err
  	}
  	singular, err = del.ResourceSingularizer(resource)
  	if err != nil && !d.cl.Fresh() {
  		d.Reset()
  		singular, err = d.ResourceSingularizer(resource)
  	}
  	return
  }
docs: // ResourceSingularizer converts a resource name from plural to
  // singular (e.g., from pods to pod).