diff --git a/fs_uae_wrapper/cd32.py b/fs_uae_wrapper/cd32.py
index fe5bc60..903babb 100644
--- a/fs_uae_wrapper/cd32.py
+++ b/fs_uae_wrapper/cd32.py
@@ -165,9 +165,8 @@ class CD32(object):
         if os.path.exists(self.save_filename):
             os.unlink(self.save_filename)
 
-        code = utils.run_command(['7z', 'a', self.save_filename,
-                                  os.path.join(self.dir, 'fs-uae-save')])
-        if code != 0:
+        if not utils.run_command(['7z', 'a', self.save_filename,
+                                  os.path.join(self.dir, 'fs-uae-save')]):
             sys.stderr.write('Error: archiving save state failed\n')
             return False
 
diff --git a/fs_uae_wrapper/utils.py b/fs_uae_wrapper/utils.py
index c3bb1fb..41405d2 100644
--- a/fs_uae_wrapper/utils.py
+++ b/fs_uae_wrapper/utils.py
@@ -3,7 +3,6 @@ Misc utilities
 """
 from distutils import spawn
 import os
-import six
 import subprocess
 import sys
 try:
@@ -109,11 +108,12 @@ def extract_archive(arch_name, show_gui_message, message_text):
 def run_command(cmd):
     """
     Run provided command. Return true if command execution returns zero exit
-    code, false otherwise. If cmd is a string, there would be an attempt to
-    split it up for subprocess call method.
+    code, false otherwise. If cmd is not a list, there would be an attempt to
+    split it up for subprocess call method. May throw exception if cmd is not
+    a list neither a string.
     """
 
-    if isinstance(six.text_type(cmd), six.string_types):
+    if not isinstance(cmd, list):
         cmd = cmd.split()
 
     code = subprocess.call(cmd)
diff --git a/requirements.txt b/requirements.txt
deleted file mode 100644
index ffe2fce..0000000
--- a/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-six
diff --git a/tests/test_cd32.py b/tests/test_cd32.py
index b456941..5e299d4 100644
--- a/tests/test_cd32.py
+++ b/tests/test_cd32.py
@@ -144,7 +144,7 @@ class TestCD32(TestCase):
         acd32 = cd32.CD32()
         acd32.dir = self.dirname
         acd32.save_filename = "foobar_save.7z"
-        run.return_value = 0
+        run.return_value = True
 
         self.assertTrue(acd32._save_save())
 
@@ -157,7 +157,7 @@ class TestCD32(TestCase):
         os.mkdir(os.path.join(self.dirname, 'fs-uae-save'))
         self.assertTrue(acd32._save_save())
 
-        run.return_value = 1
+        run.return_value = False
         self.assertFalse(acd32._save_save())
 
     @mock.patch('fs_uae_wrapper.utils.run_command')
diff --git a/tox.ini b/tox.ini
index a8bf4bf..6cc9c24 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,8 +8,7 @@ usedevelop=True
 setenv = COVERAGE_FILE = .coverage
 commands = py.test --cov=fs_uae_wrapper --cov-report=term-missing
 
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps = -r{toxinidir}/test-requirements.txt
 
 [testenv:py27]
 deps = {[testenv]deps}