I have a data.frame of length 3 - `sku_data`:
A sample of the data is:

```
sku_data <- data.frame(
  sku = c(1200337,1200518,1200586,1200590),
  units_current = I(list(c(1),1:3,1:4,2:4)),
  units_end = I(list(1:3,1,2:4,1:3))
)

#      sku units_current units_end
#1 1200337             1   1, 2, 3
#2 1200518       1, 2, 3         1
#3 1200586    1, 2, 3, 4   2, 3, 4
#4 1200590       2, 3, 4   1, 2, 3

```

I want to remove those elements where the length of `units_current` or `units_end` is `<=1`. They are both lists of lists.

Thanks