diff --git a/swh/loader/tar/utils.py b/swh/loader/tar/utils.py
index c5e9bac..b728b0a 100644
--- a/swh/loader/tar/utils.py
+++ b/swh/loader/tar/utils.py
@@ -1,74 +1,74 @@
 # Copyright (C) 2015-2017  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import itertools
 import random
 
 from swh.model import hashutil
 
 
 def convert_to_hex(d):
     """Convert a flat dictionary with bytes in values to the same dictionary
     with hex as values.
 
     Args:
         dict: flat dictionary with sha bytes in their values.
 
     Returns:
         Mirror dictionary with values as string hex.
 
     """
     if not d:
         return d
 
     checksums = {}
     for key, h in d.items():
         if isinstance(h, bytes):
             checksums[key] = hashutil.hash_to_hex(h)
         else:
             checksums[key] = h
 
     return checksums
 
 
 def grouper(iterable, n, fillvalue=None):
     """Collect data into fixed-length chunks or blocks.
 
     Args:
         iterable: an iterable
         n: size of block
         fillvalue: value to use for the last block
 
     Returns:
         fixed-length chunks of blocks as iterables
 
     """
     args = [iter(iterable)] * n
     return itertools.zip_longest(*args, fillvalue=fillvalue)
 
 
 def random_blocks(iterable, block=100, fillvalue=None):
     """Given an iterable:
     - slice the iterable in data set of block-sized elements
     - randomized the data set
     - yield each element
 
     Args:
         iterable: iterable of data
         block: number of elements per block
         fillvalue: a fillvalue for the last block if not enough values in
         last block
 
     Returns:
         An iterable of randomized per block-size elements.
 
     """
     count = 0
     for iterable in grouper(iterable, block, fillvalue=fillvalue):
         count += 1
-        l = list(iterable)
-        random.shuffle(l)
-        for e in l:
+        lst = list(iterable)
+        random.shuffle(lst)
+        for e in lst:
             yield e