My data look like this:

```
let = ['a', 'b', 'a', 'c', 'a']

```

How do I remove the duplicates? I want my output to be something like this:

```
['b', 'c']

```

When I use the `set` function, I get:

```
set(['a', 'c', 'b'])

```

This is not what I want.