Running examples in ‘flowchart-Ex.R’ failed
The error most likely occurred in:

> ### Name: fc_draw
> ### Title: fc_draw
> ### Aliases: fc_draw
> 
> ### ** Examples
> 
> safo |>
+   as_fc(label = "Patients assessed for eligibility") |>
+   fc_filter(!is.na(group), label = "Randomized", show_exc = TRUE) |>
+   fc_split(group) |>
+   fc_filter(itt == "Yes", label = "Included in ITT") |>
+   fc_filter(pp == "Yes", label = "Included in PP") |>
+   fc_draw()
Error in `dplyr::mutate()`:
ℹ In argument: `y = update_y(.data$y, .data$type, .data$x,
  .data$group)`.
ℹ In row 1.
Caused by error in `dplyr::mutate()`:
ℹ In argument: `nmax = as.numeric(...)`.
ℹ In row 1.
Caused by error in `xtfrm.data.frame()`:
! cannot xtfrm data frames
Backtrace:
     ▆
  1. ├─flowchart::fc_draw(...)
  2. │ └─flowchart:::is_class(object, "fc")
  3. ├─flowchart::fc_filter(...)
  4. │ └─flowchart:::is_class(object, "fc")
  5. ├─flowchart::fc_filter(...)
  6. │ └─flowchart:::is_class(object, "fc")
  7. ├─flowchart::fc_split(...)
  8. │ └─flowchart:::is_class(object, "fc")
  9. ├─flowchart::fc_filter(...)
 10. ├─flowchart:::fc_filter.fc(...)
 11. │ ├─dplyr::mutate(...)
 12. │ └─dplyr:::mutate.data.frame(...)
 13. │   └─dplyr:::mutate_cols(.data, dplyr_quosures(...), by)
 14. │     ├─base::withCallingHandlers(...)
 15. │     └─dplyr:::mutate_col(dots[[i]], data, mask, new_columns)
 16. │       └─mask$eval_all_mutate(quo)
 17. │         └─dplyr (local) eval()
 18. ├─flowchart:::update_y(.data$y, .data$type, .data$x, .data$group)
 19. │ ├─dplyr::mutate(...)
 20. │ └─dplyr:::mutate.data.frame(...)
 21. │   └─dplyr:::mutate_cols(.data, dplyr_quosures(...), by)
 22. │     ├─base::withCallingHandlers(...)
 23. │     └─dplyr:::mutate_col(dots[[i]], data, mask, new_columns)
 24. │       └─mask$eval_all_mutate(quo)
 25. │         └─dplyr (local) eval()
 26. ├─base::which.max(...)
 27. │ ├─base::xtfrm(`<tibble[,1]>`)
 28. │ └─base::xtfrm.data.frame(`<tibble[,1]>`)
 29. │   └─base::stop("cannot xtfrm data frames")
 30. └─base::.handleSimpleError(...)
 31.   └─dplyr (local) h(simpleError(msg, call))
 32.     └─rlang::abort(message, class = error_class, parent = parent, call = error_call)
Execution halted