title: Pandas showing only the unique instances of a value in a dataframe for a given id
body: <p>This is the dataframe I'm working with.</p>
  
  <pre><code>df = pd.DataFrame({'id' : ['45', '45', '45', '45', '46', '46'],
                    'description' : ['credit score too low', 'credit score too low', 'credit score too low', 'high risk of fraud', 'address not verified', 'address not verified']})
  print(df)
  </code></pre>
  
  <p>I'm trying to modify the the dataframe such that, for a given id, there are no duplicates of a description. The dataframe below is the desired output.</p>
  
  <pre><code>newdf = pd.DataFrame({'id' : ['45', '45', '46'],
                    'description' : ['credit score too low', 'high risk of fraud', 'address not verified']})
  print(newdf)
  </code></pre>