diff --git a/nhentai/cmdline.py b/nhentai/cmdline.py
index b14ec4d..ffc8a3e 100644
--- a/nhentai/cmdline.py
+++ b/nhentai/cmdline.py
@@ -1,5 +1,5 @@
 # coding: utf-8
-from __future__ import print_function
+
 import os
 import sys
 import json
diff --git a/nhentai/command.py b/nhentai/command.py
index 16adc22..cbc50ed 100644
--- a/nhentai/command.py
+++ b/nhentai/command.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python2.7
 # coding: utf-8
-from __future__ import unicode_literals, print_function
+
 import sys
 import signal
 import platform
diff --git a/nhentai/constant.py b/nhentai/constant.py
index bce3604..39c6f3e 100644
--- a/nhentai/constant.py
+++ b/nhentai/constant.py
@@ -1,7 +1,6 @@
 # coding: utf-8
-from __future__ import unicode_literals, print_function
+
 import os
-import copy
 import tempfile
 
 try:
diff --git a/nhentai/doujinshi.py b/nhentai/doujinshi.py
index 3c43d62..0170ad5 100644
--- a/nhentai/doujinshi.py
+++ b/nhentai/doujinshi.py
@@ -1,7 +1,6 @@
 # coding: utf-8
-from __future__ import print_function, unicode_literals
+
 from tabulate import tabulate
-from future.builtins import range
 
 from nhentai.constant import DETAIL_URL, IMAGE_URL
 from nhentai.logger import logger
diff --git a/nhentai/downloader.py b/nhentai/downloader.py
index f11bb60..4f26b6e 100644
--- a/nhentai/downloader.py
+++ b/nhentai/downloader.py
@@ -1,5 +1,4 @@
 # coding: utf-
-from __future__ import unicode_literals, print_function
 
 import multiprocessing
 import signal
diff --git a/nhentai/parser.py b/nhentai/parser.py
index 582add2..7b9142c 100644
--- a/nhentai/parser.py
+++ b/nhentai/parser.py
@@ -1,5 +1,4 @@
 # coding: utf-8
-from __future__ import unicode_literals, print_function
 
 import os
 import re
diff --git a/nhentai/utils.py b/nhentai/utils.py
index de40d94..1ce4298 100644
--- a/nhentai/utils.py
+++ b/nhentai/utils.py
@@ -1,5 +1,4 @@
 # coding: utf-8
-from __future__ import unicode_literals, print_function
 
 import sys
 import re
@@ -240,7 +239,7 @@ def format_filename(s):
     if filename include forbidden characters (\'/:,;*?"<>|) ,it replace space character(' '). 
     """
     # maybe you can use `--format` to select a suitable filename
-    ban_chars = '\\\'/:,;*?"<>|'
+    ban_chars = '\\\'/:,;*?"<>|\t'
     filename = s.translate(str.maketrans(ban_chars, ' '*len(ban_chars))).strip()
     while filename.endswith('.'):
         filename = filename[:-1]