diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..0858471
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,12 @@
+sudo: true
+language: python
+
+python:
+  - "2.7"
+  - "3.6"
+  - "3.7-dev" # 3.7 development branch
+
+install: 
+
+script: 
+  - "python setup.py install"
diff --git a/colpy/core/illum.py b/colpy/core/illum.py
index 9225b92..820d275 100644
--- a/colpy/core/illum.py
+++ b/colpy/core/illum.py
@@ -92,7 +92,7 @@ def Z(self):
 class IlluminantA(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _A_definition.keys():
+        if std_obs not in list(_A_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_A_definition.get(std_obs))
         
@@ -100,7 +100,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantB(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _B_definition.keys():
+        if std_obs not in list(_B_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_B_definition.get(std_obs))
 
@@ -108,7 +108,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantC(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _C_definition.keys():
+        if std_obs not in list(_C_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_C_definition.get(std_obs))
 
@@ -116,7 +116,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantD50(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _D50_definition.keys():
+        if std_obs not in list(_D50_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_D50_definition.get(std_obs))
 
@@ -124,7 +124,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantD55(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _D55_definition.keys():
+        if std_obs not in list(_D55_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_D55_definition.get(std_obs))
 
@@ -132,7 +132,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantD65(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _D65_definition.keys():
+        if std_obs not in list(_D65_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_D65_definition.get(std_obs))
 
@@ -140,7 +140,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantD75(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _D75_definition.keys():
+        if std_obs not in list(_D75_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_D75_definition.get(std_obs))
 
@@ -148,7 +148,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantE(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _E_definition.keys():
+        if std_obs not in list(_E_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_E_definition.get(std_obs))
 
@@ -156,7 +156,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF1(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F1_definition.keys():
+        if std_obs not in list(_F1_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F1_definition.get(std_obs))
 
@@ -164,7 +164,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF2(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F2_definition.keys():
+        if std_obs not in list(_F2_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F2_definition.get(std_obs))
 
@@ -172,7 +172,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF3(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F3_definition.keys():
+        if std_obs not in list(_F3_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F3_definition.get(std_obs))
 
@@ -180,7 +180,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF4(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F4_definition.keys():
+        if std_obs not in list(_F4_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F4_definition.get(std_obs))
 
@@ -188,7 +188,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF5(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F5_definition.keys():
+        if std_obs not in list(_F5_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F5_definition.get(std_obs))
 
@@ -196,7 +196,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF6(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F6_definition.keys():
+        if std_obs not in list(_F6_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F6_definition.get(std_obs))
 
@@ -204,7 +204,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF7(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F7_definition.keys():
+        if std_obs not in list(_F7_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F7_definition.get(std_obs))
 
@@ -212,7 +212,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF8(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F8_definition.keys():
+        if std_obs not in list(_F8_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F8_definition.get(std_obs))
 
@@ -220,7 +220,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF9(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F9_definition.keys():
+        if std_obs not in list(_F9_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F9_definition.get(std_obs))
 
@@ -228,7 +228,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF10(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F10_definition.keys():
+        if std_obs not in list(_F10_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F10_definition.get(std_obs))
 
@@ -236,7 +236,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF11(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F11_definition.keys():
+        if std_obs not in list(_F11_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F11_definition.get(std_obs))
 
@@ -244,7 +244,7 @@ def __init__(self, std_obs='1964_10'):
 class IlluminantF12(BaseIlluminant):
 
     def __init__(self, std_obs='1964_10'):
-        if std_obs not in _F12_definition.keys():
+        if std_obs not in list(_F12_definition.keys()):
             raise ValueError("unsupported CIE standard observer")
         super().__init__(*_F12_definition.get(std_obs))
 
diff --git a/doc/conf.py b/doc/conf.py
index 9e0bcf4..5fcb696 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -40,8 +40,8 @@
 master_doc = 'index'
 
 # General information about the project.
-project = u'ColPy'
-copyright = u'2011, Arlen Avakian'
+project = 'ColPy'
+copyright = '2011, Arlen Avakian'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -178,8 +178,8 @@
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
 latex_documents = [
-  ('index', 'ColPy.tex', u'ColPy Documentation',
-   u'Arlen Avakian', 'manual'),
+  ('index', 'ColPy.tex', 'ColPy Documentation',
+   'Arlen Avakian', 'manual'),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
@@ -211,6 +211,6 @@
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
 man_pages = [
-    ('index', 'colpy', u'ColPy Documentation',
-     [u'Arlen Avakian'], 1)
+    ('index', 'colpy', 'ColPy Documentation',
+     ['Arlen Avakian'], 1)
 ]