I want to remove the duplicate tuples. for example, these are the tuple values

```
(eraser,pen)
(pen,eraser)
(pen,book)
(pen,pencil)
(book,pen)
(book,pencil)
(pencil,pen)
(pencil,book)

```

I want the result as,

```
(eraser,pen)
(pen,book)
(pen,pencil)
(book,pencil)

```

Note: These tuples are in the form of (String,String)