title: adding label number to first and last observation
body: <p>I have created the following graph. I would like to annotate the first value and the last value for each of the line created in the graph. The value would be annotated for each line just before the line and at its end </p>
  
  <p>How to?</p>
  
  <pre><code>data = {'Time':['1', '2', '1', '2', '1', '2', '1', '2', '1', '2', '1', '2', '1', '2' , '1', '2'], 'Country':['Italy', 'Italy', 'Italy', 'Italy', 'Italy', 'Italy', 'Italy', 'Italy',  'Russia', 'Russia',  'Russia', 'Russia' ,  'Russia', 'Russia',  'Russia', 'Russia'], 'Score':[20, 21, 14, 15, 19, 18, 5, 9, 5, 8, 3, 3, 5, 1, 3, 8]} 
  df = pd.DataFrame(data) 
  sns.lineplot(x="Time", y="Score", hue="Country",  data=df)
  </code></pre>