how to sort lists within list in user defined order?
<p>I want to sort lists of mathematical operators (stored as strings) in order of precedence (*,/,+,-) within a list. There are thousands of lists within my list.</p>

<p>E.g.</p>

<pre><code>my_lists = [['*','+','-'],['-','*','*'],['+','/','-']]
</code></pre>

<p>should become:</p>

<pre><code>new_list = [['*','+','-'],['*','*','-'],['/','+','-']]
</code></pre>

<p>Is there a way to sort the lists within my list in a user defined order?</p>