panic: interface conversion: interface {} is nil, not map[string]interface {}

[szabgab]

I get the following exception:

go run gotube.go -v -a 'https://www.youtube.com/watch?v=QmhcdlvUIUY&list=PL3rN31hgtvRZZ6pe_brZQMOIFIBwdv5IF'

GoTube: Making a HTTP GET request thru https://www.youtube.com/get_video_info?video_id=QmhcdlvUIUY...
panic: interface conversion: interface {} is nil, not map[string]interface {}

goroutine 5 [running]:
main.DownloadYTVideo(0x7ffe90b80117, 0x53, 0x714d8c, 0x1, 0xc000040101, 0x0, 0x0)
	/home/gabor/work/gotube/gotube.go:293 +0x2315
main.Download.func1(0xc000000008, 0x72a878)
	/home/gabor/work/gotube/gotube.go:409 +0xcb
golang.org/x/sync/errgroup.(*Group).Go.func1(0xc000082c60, 0xc000012500)
	/home/gabor/go/src/golang.org/x/sync/errgroup/errgroup.go:57 +0x57
created by golang.org/x/sync/errgroup.(*Group).Go
	/home/gabor/go/src/golang.org/x/sync/errgroup/errgroup.go:54 +0x66
exit status 2

$ go version
go version go1.12.9 linux/amd64

On this commit: 3637197