code: func (p *Namespaces) Register(ns Namespace) {
  	if !p.Safe {
  		p.mu.Lock()
  		defer p.mu.Unlock()
  	}
  	if p.prefixes == nil {
  		p.prefixes = make(map[string]string)
  	}
  	p.prefixes[ns.Prefix] = ns.Full
  }
docs: // Register adds namespace to registered list.