How i can get a diffstat from a time that branch created ?

Hi,
i tried, to use diffstat and failed.

In Documentation via link https://api.bitbucket.org/2.0/repositories/bitbucket/geordi/diffstat/d222fa2..e174964

i see that i need use 2 parameters start and end commitId. But as i see i get a diff only after a start commit. I need get a diff from empty branch to end commitId