diff --git a/bin/prefix-date b/bin/prefix-date
index e6fc0c5..d82ebe7 100755
--- a/bin/prefix-date
+++ b/bin/prefix-date
@@ -1,6 +1,4 @@
-#!/usr/bin/env python
-
-from __future__ import unicode_literals, division, absolute_import, with_statement, print_function
+#!/usr/bin/env python3
 
 import os
 import re
@@ -9,43 +7,64 @@ from datetime import datetime
 from optparse import OptionParser
 from os import path
 
+
 def add(arr):
     return arr[0] + arr[1]
+
+
 assert add([1, 2]) == 3
 
+
 def mul(arr):
     return arr[0] * arr[1]
+
+
 assert mul([2, 3]) == 6
 
+
 def echo(arg):
     print(arg)
     return arg
 
+
 def compose(*funcs):
-    return lambda arg = None: reduce(lambda val, func: func(val), funcs, arg)
+    return lambda arg=None: reduce(lambda val, func: func(val), funcs, arg)
+
 
-test_compose = compose(lambda _: [2, 3], mul, lambda x: [x, 3], mul, lambda x: [x, 1], add)
+test_compose = compose(lambda _: [2, 3], mul, lambda x: [x, 3], mul, lambda \
+        x \
+    : \
+        [x, 1], add)
 # 2 * 3 = 6 * 3 = 18 + 1 = 19
 assert test_compose() == 19
 
 date_reg_ex = re.compile("\d{4}-\d{2}-\d{2}_")
-doesnt_start_with_date = lambda string: date_reg_ex.search(string, 0, 11) is None
+doesnt_start_with_date = lambda string: \
+        date_reg_ex.search(string, 0, 11) is None
 assert doesnt_start_with_date("1234-56-78_") == False
 assert doesnt_start_with_date("a1234-56-78_")
 assert doesnt_start_with_date("1234-56-78")
-assert doesnt_start_with_date("1234-56-78_ sdfsakdsdf fjalsdjhfaskj  ldfh") == False
+assert \
+    doesnt_start_with_date("1234-56-78_ sdfsakdsdf fjalsdjhfaskj  ldfh") == False
+
 
 def prop(key):
     def obj(dic):
         return dic[key]
+
     return obj
+
+
 assert prop('key')({'key': 1}) == 1
 
+
 def path_join(directory):
     def do_join(file_name):
         return path.join(directory, file_name)
+
     return do_join
 
+
 def mk_dir_map(ret, directory):
     is_file = compose(path_join(directory), path.isfile)
     files = filter(is_file, os.listdir(directory))
@@ -53,52 +72,46 @@ def mk_dir_map(ret, directory):
     ret[directory] = map(lambda x: {'original': x}, not_with_date)
     return ret
 
+
 def add_date(ret, directory):
     original = prop('original')
     add_dir_name = path_join(directory)
+
     def list_date(file_obj):
-        date_from_obj = compose(
-            original,
-            add_dir_name,
-            path.getctime,
-            datetime.fromtimestamp
-        )
+        date_from_obj = compose(original, add_dir_name, path.getctime, datetime.fromtimestamp)
         date = date_from_obj(file_obj)
-        file_obj['new'] = date.strftime('%Y-%m-%d_{0}'.format(original(file_obj)))
+        file_obj[
+            'new'
+        ] = date.strftime('%Y-%m-%d_{0}'.format(original(file_obj)))
         return file_obj
 
     ret[directory] = map(list_date, ret[directory])
     return ret
 
+
 def rename(ret, directory):
-    original = compose(
-        prop('original'),
-        path_join(directory),
-    )
-    new = compose(
-        prop('new'),
-        path_join(directory),
-    )
+    original = compose(prop('original'), path_join(directory))
+    new = compose(prop('new'), path_join(directory))
+
     def do_rename(file_obj):
         os.rename(original(file_obj), new(file_obj))
         return echo("mv -v {0} {1}".format(original(file_obj), new(file_obj)))
+
     map(do_rename, ret[directory])
     return ret
 
+
 def main(options, directories):
     real_directories = filter(path.isdir, directories)
     file_tree = reduce(mk_dir_map, real_directories, {})
     file_tree = reduce(add_date, file_tree, file_tree)
     file_tree = reduce(rename, file_tree, file_tree)
 
+
 if __name__ == '__main__':
     parser = OptionParser()
-    parser.add_option("-f", "--file", dest="filename",
-                              help="write report to FILE", metavar="FILE")
-    parser.add_option("-q", "--quiet",
-                              action="store_false", dest="verbose", default=True,
-                                                help="don't print status messages to stdout")
+    parser.add_option("-f", "--file", dest="filename", help="write report to FILE", metavar="FILE")
+    parser.add_option("-q", "--quiet", action="store_false", dest="verbose", default=True, help="don't print status messages to stdout")
 
-    (options, args) = parser.parse_args()
+    options, args = parser.parse_args()
     main(options, args)
-