You want something like:

[self dismissViewControllerAnimated:YES completion:^{
            ...
            &lt;do something on completion here&gt;
            ...
        }];


dismissViewControllerAnimated completion method not working
Does there exist a quasi-isometric embedding 
$$MCG(S) \to (\mathrm{Teich}(S), d)$$ 
for $d$ any "known" distance on the Teichmuller space (i.e. Teichmuller, Weil-Petersson, Thurston...) ?   
