Adjust the Flask version required according to the version of python used
diff --git a/setup.py b/setup.py
index 639a5ae..7232f22 100644
--- a/setup.py
+++ b/setup.py
@@ -27,12 +27,11 @@
     sys.exit(1)
 
 extra = {}
-install_requires = ['Flask>=0.10.1']
 if sys.version_info >= (3,):
-    install_requires.append('python3-openid>=2.0')
+    install_requires = ['Flask>=0.10.1', 'python3-openid>=2.0']
     extra['use_2to3'] = True
 else:
-    install_requires.append('python-openid>=2.0')
+    install_requires = ['Flask>=0.3', 'python-openid>=2.0']
 
 setup(
     name='Flask-OpenID',