remove unsused utitlity function

IPython/utils/data.py

@@ -1,36 +1,30 b''
 # encoding: utf-8
 """Utilities for working with data structures like lists, dicts and tuples.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 
 def uniq_stable(elems):
     """uniq_stable(elems) -> list
 
     Return from an iterable, a list of all the unique elements in the input,
     but maintaining the order in which they first appear.
 
     Note: All elements in the input must be hashable for this routine
     to work, as it internally uses a set for efficiency reasons.
     """
     seen = set()
     return [x for x in elems if x not in seen and not seen.add(x)]
 
 
-def flatten(seq):
-    """Flatten a list of lists (NOT recursive, only works for 2d lists)."""
-
-    return [x for subseq in seq for x in subseq]
-    
-
 def chop(seq, size):
     """Chop a sequence into chunks of the given size."""
     return [seq[i:i+size] for i in range(0,len(seq),size)]