title: How to Display selected values from a dictionary to a listbox
body: <p>I'm busy making a program with a search function where a person will enter for example subject "Information Systems" in a GUI Tk entry, and i want it to display on those records which has Information systems. Here is some code:</p>
  
  <pre><code>StudentList[[Tom,Information systems],[John,Computers]]
  </code></pre>
  
  <p>So basically if I type Information systems, it must show in my listbox:
  "Tom, Information Systems"</p>
  
  <p>How do i make this search function work?
  This is what i have tried</p>
  
  <pre><code>for i in students:
      if viewcode == True:
          lb1.insert(END,str(i))
  </code></pre>