- cmp
 - no destructuring for lambda arguments
 - xrange -> range
 - Fix relative imports.
 - generators -> list
 - iteritems
 - fix use of filter on strings
 - can't use -1 for level in __import__
 - duplicate enum value
 - except statment syntax.
 - func_name
 - izip
 - integer literals starting with 0
 - exec can't set local variables
 - sorting
 - integer vs float division