## Lists and List Comprehensions

- Using either Kapulet's or Haskell's list comprehension syntax, write an expression that transforms
`[3, 1, 0, 2]`

into`[3, 3, 3, 1, 2, 2]`

.

*Here is a hint*

Define a function `dup (n, x)`

that creates a list of *n* copies of `x`

. Then use list comprehensions to transform `[3, 1, 0, 2]`

into `[[3, 3, 3], [1], [], [2, 2]]`

. Then use `join`

to "flatten" the result.