title: Plot multiple lines in a line graph using matplotlib
body: <p>I am trying to plot a line graph with several lines in it, one for each group. 
  X axis would be the hour and y axis would be the count.
  Since there are 3 groups in the dataframe, i will have 3 lines in a single line graph.
  This is the code I have used but not sure where I am going wrong. </p>
  
  <pre><code>Group      Hour           Count
   G1          1             40
   G2          1             300
   G1          2             400
   G2          2             80
   G3          2             1211
  </code></pre>
  
  <p>Code used:</p>
  
  <pre><code>fig, ax = plt.subplots()
  labels = []
  for key, grp in df1.groupby(['Group']):
    ax = grp.plot(ax=ax, kind='line', x='x', y='y', c=key)
    labels.append(key)
  lines, _ = ax.get_legend_handles_labels()
  ax.legend(lines, labels, loc='best')
  plt.show()
  </code></pre>