title: Finding minimum value in dictionary
body: <p>I have a dictionary with grades. When I ask for the minimum value it gives me the largest value. I used the <code>min(Grades)</code> to find the minimum but it was me the largest then I found <code>min(Grades.items(), key=lambda x:x[1])</code> and it worked but I don't get why the min(Grades) doesn't work. I also have no idea how the <code>min(Grades.items(), key=lambda x: x[1])</code> works and what it means.</p>
  
  <pre><code>&gt;&gt;&gt; Grades
  {'pr': [17, 15], 'hw': [16, 27, 25], 'ex': [83, 93], 'qz': [8, 10, 5]}
  &gt;&gt;&gt; min(Grades)
  'ex'
  &gt;&gt;&gt; min(Grades.items(), key=lambda x: x[1])
  ('qz', [8, 10, 5])
  </code></pre>