<pre>
DataFrame <code>employees</code>
+-------------+--------+
| Column Name | Type   |
+-------------+--------+
| name        | object |
| salary      | int    |
+-------------+--------+
</pre>

<p>A company intends to give its employees a pay rise.</p>

<p>Write a solution to <strong>modify</strong> the <code>salary</code> column by multiplying each salary by 2.</p>

<p>The result format is in the following example.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:
</strong>DataFrame employees
+---------+--------+
| name    | salary |
+---------+--------+
| Jack    | 19666  |
| Piper   | 74754  |
| Mia     | 62509  |
| Ulysses | 54866  |
+---------+--------+
<strong>Output:
</strong>+---------+--------+
| name    | salary |
+---------+--------+
| Jack    | 39332  |
| Piper   | 149508 |
| Mia     | 125018 |
| Ulysses | 109732 |
+---------+--------+
<strong>Explanation:
</strong>Every salary has been doubled.</pre>