How To Merge 3 lists into one dictionary(with unique elements)
<h3>Code Written In Python</h3>

<blockquote>
  <p><code># Following Are The 3 Lists</code><br>
  <code>sections = ['A', 'B', 'A', 'A', 'B']</code><br>
  <code>students = ['Jack', 'Jim', 'Jack', 'Leena', 'Jim']</code><br>
  <code>subjects = ['Maths', 'Biology', 'Chemistry', 'English', 'Physics']</code></p>
  
  <p><code># The Output Should Be A Dictionary</code><br>
      <code>classDict = {'A':{'Jack' :{1:'Maths', 2:'Chemistry'}, 'Leena':{1:'English'}}, 'B':{'Jim':{1:'Biology', 2:'Physics'}}}</code>  </p>
</blockquote>

<p>I can merge any of the two list into one dictionary, taking only first two lists in account</p>

<pre><code>classDict = {}   
for stu in students:  
    if not stu in classDict:     
        classDict[stu] = []    
    classDict[stu].append(stu)  
</code></pre>

<p>But unable to extend it to n(n=3, in my case) list.</p>
