title: Histogram bin size
body: <p>I have a code like this and I am wondering why my bin size of the two plotted graphs is different?</p>
  
  <pre><code>import matplotlib.pyplot as pyplot
  bins=15
  pyplot.rcParams["figure.figsize"] = (10,10)
  
  #echte_Ladezeit
  pyplot.hist(Y_test, bins, alpha=1, label='Y_test; orange Dateien', 
  color='orange', weights = np.ones_like(Y_test)/float(len(Y_test)))
  pyplot.hist(Y_train, bins, alpha=1, label='Y_train; grüne Dateien', 
  color='green', weights = np.ones_like(Y_train)/float(len(Y_train)))
  pyplot.title('Verteilung echte_Ladezeit')
  pyplot.xlabel('echte_Ladezeit')
  pyplot.ylabel('Häufigkeit [%]')
  pyplot.legend(loc='upper right')
  pyplot.show()
  </code></pre>
  
  <p>actually the marked width of the orange and the green one should be the same right? Do I have any mistake in my code?
  <a href="https://i.stack.imgur.com/2Cjho.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2Cjho.png" alt="enter image description here"></a></p>