why don't design a API to check namespace exist like #tableExists

[小展]

Hi, guys
        In Admin class , we still  haven’t a  api to check  the namespace exist 
. Now ,  when I  want to check a namespace exist in my cluster , I  use  
#getNamespaceDescriptor。 If catch NamespaceNotFoundException than return 
false，otherwise return true . I don’t think that’s a good  way . And I also 
find in   TableNamespceManager class we used doesNamespaceExist(final String 
namespaceName) to check  namespace exist . 

I don’t know is there I miss something . 

If you have better way Or we should add a api ? Please tell me .