chained.clj

(def collection [1 2 [3 4] [4 5] 6 7 [7 8]])

(println 
 (->> collection
      flatten
      (map #(* % 2))         ; this could use the #(* % 2) lambda shorthand
      distinct
      sort))
; => (2 4 6 8 10 12 14 16)

chained.py

from functools import partial
from flatten import flatten

def thread(arg, *sequence):
    """An implementation of Clojure's ->> function"""
    for item in sequence:
        arg = item(arg)
    return arg


collection = [1, 2, [3, 4], [4, 5], 6, 7, [7, 8]]

print thread(collection,
             flatten,
             partial(map, lambda x: x * 2),
             set,
             sorted)

flatten.py

def flatten(items):
  """A recursive flatten function."""
  if len(items) == 0:
      return []
  elif len(items) == 1:
      first, rest = items[0], []
  else:
      first, rest = items[0], items[1:]

  if type(first) is list:
      result = flatten(first)
  else:
      result = [first]

  return result + flatten(rest)

unchained.clj

(def collection [1 2 [3 4] [4 5] 6 7 [7 8]])

; unchained version
(println 
 (sort
  (distinct 
   (map #(* % 2)
        (flatten collection)))))

unchained.py

from flatten import flatten

collection = [1, 2, [3, 4], [4, 5], 6, 7, [7, 8]]

print sorted(set(map(lambda x: x * 2, flatten(collection))))