auto subtypes = resource_type.getSubtypes();
  if (subtypes.size() == 1) return subtypes[0];
  return nullptr;
}

// Replaces all `tf.VarIsInitializedOp` in a block with a constant true.
// TODO(b/171039585): Replace this with proper analysis of
// `tf.VarIsInitializedOp` in regards to resource writes and control flow.
void SetAllVarIsInitializedToTrue(Block* block) {
  auto builder = OpBuilder::atBlockBegin(block);