package main

import "fmt"

type Registry interface {
	Register(address string, id string) error
	Get(id string) (*string, error)
}

type MemoryRegistry struct {
	registry map[string]string
}

func (r *MemoryRegistry) Register(address string, id string) error {
	r.registry[id] = address
	return nil
}

func (r *MemoryRegistry) Get(id string) (*string, error) {
	addr, ok := r.registry[id]
	if !ok {
		return nil, fmt.Errorf("id not found")
	}
	return &addr, nil
}