code: private boolean areChildrenComputableAsPyExprs(ParentSoyNode<?> node) {
  
      for (SoyNode child : node.getChildren()) {
        // Note: Save time by not visiting RawTextNode and PrintNode children.
        if (!(child instanceof RawTextNode) && !(child instanceof PrintNode)) {
          if (!visit(child)) {
            return false;
          }
        }
      }
  
      return true;
    }
docs: Private helper to check whether all SoyNode children of a given parent node satisfy
  IsComputableAsPyExprVisitor. ExprNode children are assumed to be computable as PyExprs.
  
  @param node The parent node whose children to check.
  @return True if all children satisfy IsComputableAsPyExprVisitor.