title: subplot with plotly with multiple traces
body: <p>i am trying to create subplots for the following plots:</p>
  
  <p><a href="https://i.stack.imgur.com/jDN2R.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jDN2R.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/CUAxV.png" rel="noreferrer"><img src="https://i.stack.imgur.com/CUAxV.png" alt="enter image description here"></a></p>
  
  <p>the code i used for the the plots are  :</p>
  
  <pre><code>radius_mean1 = df[df['diagnosis']==1]['radius_mean']
  radius_mean0 = df[df['diagnosis']==0]['radius_mean']
  
  trace_rm1 = go.Histogram(x = radius_mean1, opacity = 0.75, name = 'malignant')
  trace_rm2 = go.Histogram(x = radius_mean0, opacity = 0.75, name = 'benign')
  
  data2 = [trace_rm1,trace_rm2]
  layout2 = go.Layout(barmode = 'overlay', title = 'radius mean')
  fig2 = go.Figure(data=data2, layout=layout2)
  
  py.iplot(fig2)
  </code></pre>
  
  <p>and similar for the other plot</p>
  
  <p>now i use the following code i found to create subplots:</p>
  
  <pre><code>fig.append_trace(fig1['data'][1], 1, 1)
  fig.append_trace(fig2['data'][0], 2, 1)
  py.iplot(fig)
  </code></pre>
  
  <p>and i get this :
  <a href="https://i.stack.imgur.com/fOQvb.png" rel="noreferrer"><img src="https://i.stack.imgur.com/fOQvb.png" alt="enter image description here"></a></p>
  
  <p>how do i add both benign and malignant results to the subplots ?
  i cant seem to edit the [0] or [ 1] to show both ie have the first 2 plots exactly into my subplot showing both malignant and benign and not just one or the other.</p>