[bug]: wrapping crashes with what I guess is nothing to wrap ("")

[Melkiades]

lyt <- basic_table(title = "") %>% # if title = " " or nothing in the parenthesis it works fine
    split_rows_by("SEX", page_by = TRUE) %>%
    analyze("AGE")

tbl <- build_table(lyt, DM)

res <- export_as_pdf(tbl, file = "to_d.pdf")

table is:

> tbl
                   all obs
--------------------------
F                         
  Mean              34.13 
M                         
  Mean              34.32 
U                         
  Mean               NA   
UNDIFFERENTIATED          
  Mean               NA   

error is:

> res <- export_as_pdf(tbl, file = "to_d.pdf")
Error in wrap_string(xi, max_width) : 
  is.character(str) && length(str) == 1 is not TRUE