Fix `gocyclo` errors

[mrpalide]

After fixing ticket #1865 and adding gocyclo to formatting process in CI (and local), we get about 14 errors there! So we just ignore them for now, but should solve them. Those ignored errors could be founding by TODO: fix gocyclo error. or gocyclo:ignore, e.g. :

// TODO: fix gocyclo error.
//
//gocyclo:ignore
func makeTree() {