}

    auto called_computations = op.getCalledComputations();
    if (called_computations.size() != 1) {
      return op.emitOpError()
             << "ApproxTopK takes exactly 1 called_computation.";
    }
    mlir::func::FuncOp callee = module_op_->lookupSymbol<mlir::func::FuncOp>(
        mlir::cast<FlatSymbolRefAttr>(op.getCalledComputations()[0]));