Add print_function for py2

rdf/helpers.py

@@ -1,5 +1,5 @@
 import sys
-from future.standard_library import install_aliases
+from future.standard_library import install_aliases, print_function
 install_aliases()
 
 from urllib import request, parse
@@ -124,4 +124,4 @@ def check(testname):
     definition = solution(testname)
     if definition is None:
         raise Exception('The definition for {} is empty or invalid.'.format(testname))
-    return test(definition)
+    return test(definition)

rdf/tests.py

@@ -1,3 +1,4 @@
+from future.standard_library import print_function
 import operator
 import types
 import sys
@@ -90,4 +91,4 @@ def test_example(g):
          len(g))
     test('A person has been defined',
          g.subjects(RDF.type, term.URIRef('http://xmlns.com/foaf/0.1/Person')))
-    print('All tests passed. Well done!')
+    print('All tests passed. Well done!')