title: how to reduce the time of python import modules?
body: <p>for example:</p>
  
  <pre><code>In [5]: import time
  In [6]: def test():
     ...:     t0=time.clock()
     ...:     import pandas as pd
     ...:     import numpy  as np
     ...:     import matplotlib.pyplot as plt
     ...:     t1=time.clock()
     ...:     print t1-t0
     ...:
  
  In [7]: test()
  10.8699593575
  </code></pre>
  
  <p>on my computer those statements consume over 10 second, 
  so when debugging, it's little annoying to run python script using those module.</p>
  
  <p>it's there is good way to solve it?  </p>