::  graph-store|remove-signatures: remove signatures from a node at a
::  particular uid
::
/-  *graph-store
:-  %say
|=  $:  [now=@da eny=@uvJ =beak]
        [[[=resource =index] =signatures ~] ~]
    ==
:-  %graph-update
^-  update
[%0 now [%remove-signatures [resource index] signatures]]