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<span style="font-family: verdana,serif;">
  Checks for cases when you rewrite loop variable with inner loop
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<pre style="font-family: monospace">
    for i in xrange(5):
      for i in xrange(20, 25):
          print("Inner", i)
      print("Outer", i)
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<span style="font-family: verdana,serif;">
  It also warns you if variable declared in <code>with</code> statement is redeclared inside of statement body:
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<pre style="font-family: monospace">
    with open("file") as f:
      f.read()
      with open("file") as f:
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