code: func WithNPeers(ctx context.Context, n int) (Mocknet, error) {
  	m := New(ctx)
  	for i := 0; i < n; i++ {
  		if _, err := m.GenPeer(); err != nil {
  			return nil, err
  		}
  	}
  	return m, nil
  }
docs: // WithNPeers constructs a Mocknet with N peers.