diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..7d03ea8
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,20 @@
+sudo: false
+language: python
+python:
+  - "2.7"
+  - "3.2"
+  - "3.3"
+  - "3.4"
+  - "3.5"
+  - "3.6"
+  - "3.7-dev" # 3.7 development branch
+
+install: "pip install -r requirements.txt; pip install tox-travis"
+env:
+  - TOXENV=pep8
+  - TOXENV=coverage
+script: tox
+before_install:
+  - pip install codecov
+after_success:
+  - codecov
\ No newline at end of file
diff --git a/backspinpy/Cef_tools.py b/backspinpy/Cef_tools.py
index 9d56f8a..c9fbfe4 100644
--- a/backspinpy/Cef_tools.py
+++ b/backspinpy/Cef_tools.py
@@ -40,7 +40,7 @@
 # attribute_values_list2 = cef.col_attr_values[2]
 # ...
 
-from builtins import str as unicode
+from builtins import str as str
 from io import open
 from builtins import range
 
@@ -73,7 +73,7 @@ def update(self):
         self.rows = len(self.matrix)
         self.cols = len(self.matrix[0])
         self.tab_fields = max(7, self.cols + self.row_attr + 1)
-        self.linestr = u'%s' + u'\t%s' * (self.tab_fields-1) + u'\n'
+        self.linestr = '%s' + '\t%s' * (self.tab_fields-1) + '\n'
 
     def add_header(self, name, value):
         self.header_names.append(name)
@@ -130,7 +130,7 @@ def readCEF(self, filepath, matrix_dtype = 'auto'):
                 try:
                     self.matrix.append( [matrix_dtype(el) for el in linelist[self.row_attr+1:] ])
                 except ValueError:
-                    print(repr(el), ' is invalid')
+                    print((repr(el), ' is invalid'))
 
 
 
@@ -138,24 +138,24 @@ def writeCEF(self, filepath, matrix_str_fmt = '%i'):
         self.update()
         with open(filepath, 'w') as fout:
             #Write cef file first line
-            fout.write( self.linestr % ( ('CEF', unicode(self.headers), unicode(self.row_attr),\
-                unicode(self.col_attr) , unicode(self.rows), unicode(self.cols), unicode(self.flags) ) +\
+            fout.write( self.linestr % ( ('CEF', str(self.headers), str(self.row_attr),\
+                str(self.col_attr) , str(self.rows), str(self.cols), str(self.flags) ) +\
                 ('',) * (self.tab_fields - 7) ) )
             #Write header
             for i in range(self.headers):
-                fout.write(self.linestr % ( (unicode( self.header_names[i]), unicode( self.header_values[i]) ) + ('',) * (self.tab_fields - 2) ))
+                fout.write(self.linestr % ( (str( self.header_names[i]), str( self.header_values[i]) ) + ('',) * (self.tab_fields - 2) ))
             #Write col attributes
             for i in range( self.col_attr ):
-                fout.write( self.linestr % ( ('',) * (self.row_attr) + (unicode( self.col_attr_names[i] ),) + tuple( unicode(el) for el in self.col_attr_values[i] ) ))
+                fout.write( self.linestr % ( ('',) * (self.row_attr) + (str( self.col_attr_names[i] ),) + tuple( str(el) for el in self.col_attr_values[i] ) ))
             #Write headers of row attributes
-            fout.write( self.linestr % ( tuple(unicode(el) for el in self.row_attr_names) + ('',)*(self.tab_fields-self.row_attr) ) )
+            fout.write( self.linestr % ( tuple(str(el) for el in self.row_attr_names) + ('',)*(self.tab_fields-self.row_attr) ) )
             #Write rows
             for i in range(self.rows):
                 for j in range(self.row_attr):
-                    fout.write(unicode(self.row_attr_values[j][i]) + u'\t')
-                fout.write(u'\t')
-                fout.write(u'\t'.join([unicode(matrix_str_fmt % el) for el in self.matrix[i]] ) )
-                fout.write(u'\n')
+                    fout.write(str(self.row_attr_values[j][i]) + '\t')
+                fout.write('\t')
+                fout.write('\t'.join([str(matrix_str_fmt % el) for el in self.matrix[i]] ) )
+                fout.write('\n')
 
 
 
diff --git a/backspinpy/__init__.py b/backspinpy/__init__.py
index 2b92ec8..5b7711f 100644
--- a/backspinpy/__init__.py
+++ b/backspinpy/__init__.py
@@ -1,3 +1,3 @@
-from __future__ import absolute_import
+
 from .backSPIN import SPIN, backSPIN, fit_CV, feature_selection
 from .Cef_tools import CEF_obj
diff --git a/backspinpy/backSPIN.py b/backspinpy/backSPIN.py
index 02bc3bd..baf9208 100755
--- a/backspinpy/backSPIN.py
+++ b/backspinpy/backSPIN.py
@@ -34,7 +34,7 @@
 # pyinstaller -F backSPIN.py -n backspin-mac-64-bit
 #
 
-from __future__ import division, print_function, absolute_import
+
 from numpy import *
 import getopt
 import sys