title: Bokeh Histogram of Roulette Game not showing up, am I missing something?
body: <p><strong>So I'm making a roulette game, here are the guidelines:</strong></p>
  <p>Roulette is a casino game that involves a steel ball spinner around a wheel. There are 38 slots where the ball might drop. 18 of those slots are colored red, another 18 are colored black and 2 are colored green. When you bet on either red or black and win, you get back twice the amount of your original bet. For example, if you bet $1, you would get an extra $1 for winning, but you would lose that original $1 if you lost.</p>
  <p>Simulate 200 people playing roulette, each betting $1 on red 100 times.
  Create a line chart and an appropriate histogram that describes these results.
  Make sure to label your line chart and histogram.</p>
  <hr />
  <p>So I believe my code for the game is right, but the histogram is showing up as a blank graph without anything on it.
  Am I missing something? Is there something else I need to add or incorporate?</p>
  <hr />
  <p><strong>Here's what I have written for this.</strong></p>
  <pre><code>import math
  import random
  import numpy as np
  from bokeh.plotting import figure, show
  
  def roulette(x):
      results = []
      count = 0
      for i in range(1, x):
          roll = random.randint(1, 38)
          if roll &lt;= 18:
              count += 1
              results.append(count/i)
          else:
              count -= 1
              results.append(count/i)
     
      return results
  
  def listf(x):
      for i in range(x):
          return(roulette(100)[-1])
  
  roulette_list = listf(200)
  
  hist = np.histogram(roulette_list, bins = 10, range = (0, 200))
  
  yval = hist[0]
  xval = hist[1]
  
  xbarwidth = xval[1] - xval[0]
  
  xval = xval + xbarwidth/2
  xval = xval[0:-1]
  
  print(xval)
  
  f = figure()
  for x, y in zip(xval, yval):
      f.vbar(x, xbarwidth, y, line_color = &quot;white&quot;)
  
  show(f)
  </code></pre>