Rectangling data: special cases

df_unnamed_heterogeneous <- tribble(
  ~x, ~y,
  "a", list(1),
  "b", list("a", TRUE, 5)
)
df_unnamed_heterogeneous

## # A tibble: 2 × 2
##   x     y         
##   <chr> <list>    
## 1 a     <list [1]>
## 2 b     <list [3]>