<p>Write a method to return all subsets of a set. The elements in a set are&nbsp;pairwise distinct.</p>



<p>Note: The result set should not contain duplicated subsets.</p>



<p><strong>Example:</strong></p>



<pre>

<strong> Input</strong>:  nums = [1,2,3]

<strong> Output</strong>: 

[

  [3],

&nbsp; [1],

&nbsp; [2],

&nbsp; [1,2,3],

&nbsp; [1,3],

&nbsp; [2,3],

&nbsp; [1,2],

&nbsp; []

]

</pre>