Implementation of radix sort in Python

radix.py

import math
import functools

""" radix_sort
in: list_to_sort (list)
in: base (optional)
out: sorted list_to_sort
"""
def radix_sort(list_to_sort,base=10):
  # number of significant digits of largest number
  sig_digits = math.ceil(math.log(max(list_to_sort),base))
    
  """ recurse
  in: list_to_sort (list)
  in: i (int): significant digit we are on
  out: list_to_sort (base case) or call to itself
  """
  def recurse(list_to_sort,place):
    if place == sig_digits:
      return list_to_sort
    else:
      # one list per available digit in this base
      all_digits = [[] for i in base]
      # sort each number according to the digit in place position
      for number in list_to_sort:
        all_digits[math.floor(number % base**(place+1) / base**place)].append(number)
      return recurse(functools.reduce(lambda a,b: a+b,all_digits),place+1)
  return recurse(list_to_sort,0)

""" tests
"""
def tests():
  print(radix_sort([1,15,104,207,381,245,76,72,173]))
  print(radix_sort([1001,1101,1010,10,110,1011],2))
  
tests()