title: y-axis not showing correct values in matplotlib.animation
body: <p>This code constructs a matplotlib figure, gets data using the get_data function from a webpage in the open, high, low, close format and appends these values to a list every five minutes using FuncAnimation which then updates a candlestick chart.  However, the y axis values are not correct as they display only 1-7 and should be current S&amp;P prices of around 2500.  How to fix?    </p>
  
  <pre><code>import matplotlib.pyplot as plt
  from matplotlib.finance import candlestick2_ohlc
  import matplotlib.animation as animation
  from matplotlib import style
  from es_cme_quote import get_data
  import numpy as np
  
  style.use('ggplot')
  fig=plt.figure()
  ax= fig.add_subplot(111)
  o_array=[]
  h_array=[]
  l_array=[]
  c_array=[]
  def update(dummy):
  
      [O,H,L,C]=get_data()
  
      def append_var(x,y):
          y.append(x)
  
      append_var(O[0],o_array)
      append_var(H[0],h_array)
      append_var(L[0],l_array)
      append_var(C[0],c_array)
      ax.clear()
      candlestick2_ohlc(ax,o_array,h_array,l_array,c_array,
      width=.8,colorup='g',colordown='r',alpha=1.0)
  
  anime=animation.FuncAnimation(fig,update,interval=300000)
  plt.show()
  </code></pre>