title: How to reset global variable in a subsequent import
body: <p>I have 3 modules.</p>
  
  <p><em>a.py</em>
  <br>
  global _message<br>
  def somefunc():<br>
  ...#update _message<br>
  ...print (_message)<br></p>
  
  <p><br>
  <em>b.py</em>
  <br>
  import a<br>
  def someotherfunc():<br>
  ...return None<br></p>
  
  <p><br>
  <em>c.py</em>
  <br>
  def corefunc():
  <br>
  ...import b<br>
  ...for m in n:<br>
  ......#do some steps<br>
  ......if _message:<br>
  .........do some more
  <br>
  <br></p>
  
  <p>My problem is... because _message is global, there is a residual value per iteration in c.py. </p>
  
  <p>How do I cleanup _message for each iteration in c.py?</p>