Added snippet for unique_elements in an array

snippets/unique_elements.md

@@ -0,0 +1,14 @@
+### unique_elements
+
+Returns the unique elements in a given list.
+
+The given `list` is first converted to a `set` using the `set()` function. By definition, a `set` cannot have duplicate elements. So, the duplicate elements are automatically removed. Before returning, we convert it back to a `list`
+
+``` python
+def unique_elements(li):
+    return list(set(li))
+```
+
+``` python
+unique_elements([1, 2, 2, 3, 4, 3]) # [1, 2, 3, 4]
+```