diff --git a/docs/test_feature_type.html b/docs/test_feature_type.html
index 919b0eb..1949afa 100644
--- a/docs/test_feature_type.html
+++ b/docs/test_feature_type.html
@@ -56,27 +56,27 @@ <h2 id="toc-title">Table of contents</h2>
 <p>getObject subject: https://w3id.org/isample/vocabulary/sampledfeature/1.0/testfeaturevocabulary</p>
 <p>getObject predicate: http://www.w3.org/2004/02/skos/core#prefLabel</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc8fd01580&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f177623fcb0&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/sampledfeature/1.0/testfeaturevocabulary</p>
 <p>getObject predicate: http://purl.org/dc/terms/modified</p>
 <p>length of qres: 0</p>
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+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f177715c530&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/sampledfeature/1.0/testfeaturevocabulary</p>
 <p>getObject predicate: http://www.w3.org/2004/02/skos/core#definition</p>
 <p>length of qres: 0</p>
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+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f17760a0560&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/sampledfeature/1.0/testfeaturevocabulary</p>
 <p>getObject predicate: http://www.w3.org/2000/01/rdf-schema#comment</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc9028d880&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f177715d4f0&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/sampledfeature/1.0/testfeaturevocabulary</p>
 <p>getObject predicate: http://www.w3.org/2004/02/skos/core#historyNote</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc8f1f9d60&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f17760a2180&gt;</p>
 <p><span id="ConceptScheme"></span></p>
 <section id="concept-scheme-conceptscheme" class="level1" data-number="1">
 <h1 data-number="1"><span class="header-section-number">1</span> <strong>Concept scheme:</strong> ConceptScheme</h1>
diff --git a/docs/test_feature_type.md b/docs/test_feature_type.md
index 71ca3cc..117dd8c 100644
--- a/docs/test_feature_type.md
+++ b/docs/test_feature_type.md
@@ -12,7 +12,7 @@ getObject predicate: http://www.w3.org/2004/02/skos/core#prefLabel
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc8fd01580>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f177623fcb0>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -27,7 +27,7 @@ getObject predicate: http://purl.org/dc/terms/modified
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc9028cc50>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f177715c530>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -42,7 +42,7 @@ getObject predicate: http://www.w3.org/2004/02/skos/core#definition
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc8f1f9b20>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f17760a0560>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -57,7 +57,7 @@ getObject predicate: http://www.w3.org/2000/01/rdf-schema#comment
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc9028d880>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f177715d4f0>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -72,7 +72,7 @@ getObject predicate: http://www.w3.org/2004/02/skos/core#historyNote
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7efc8f1f9d60>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f17760a2180>
 
 ---
 comment: | 
diff --git a/docs/test_sample_type.html b/docs/test_sample_type.html
index 33deb55..1b00807 100644
--- a/docs/test_sample_type.html
+++ b/docs/test_sample_type.html
@@ -56,27 +56,27 @@ <h2 id="toc-title">Table of contents</h2>
 <p>getObject subject: https://w3id.org/isample/vocabulary/specimentype/1.0/testvocabulary</p>
 <p>getObject predicate: http://www.w3.org/2004/02/skos/core#prefLabel</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94df6cfdd0&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe13878d040&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/specimentype/1.0/testvocabulary</p>
 <p>getObject predicate: http://purl.org/dc/terms/modified</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94df750770&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1395703e0&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/specimentype/1.0/testvocabulary</p>
 <p>getObject predicate: http://www.w3.org/2004/02/skos/core#definition</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94de699160&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1384b9970&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/specimentype/1.0/testvocabulary</p>
 <p>getObject predicate: http://www.w3.org/2000/01/rdf-schema#comment</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94df751160&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1395707a0&gt;</p>
 <p>getObject prefixes: PREFIX skos: <a href="http://www.w3.org/2004/02/skos/core#" class="uri">http://www.w3.org/2004/02/skos/core#</a> PREFIX owl: <a href="http://www.w3.org/2002/07/owl#" class="uri">http://www.w3.org/2002/07/owl#</a> PREFIX rdf: <a href="http://www.w3.org/1999/02/22-rdf-syntax-ns#" class="uri">http://www.w3.org/1999/02/22-rdf-syntax-ns#</a> PREFIX rdfs: <a href="http://www.w3.org/2000/01/rdf-schema#" class="uri">http://www.w3.org/2000/01/rdf-schema#</a></p>
 <p>getObject subject: https://w3id.org/isample/vocabulary/specimentype/1.0/testvocabulary</p>
 <p>getObject predicate: http://www.w3.org/2004/02/skos/core#historyNote</p>
 <p>length of qres: 0</p>
-<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94de698350&gt;</p>
+<p>qres: &lt;rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1384ba2a0&gt;</p>
 <p><span id="ConceptScheme"></span></p>
 <section id="concept-scheme-conceptscheme" class="level1" data-number="1">
 <h1 data-number="1"><span class="header-section-number">1</span> <strong>Concept scheme:</strong> ConceptScheme</h1>
diff --git a/docs/test_sample_type.md b/docs/test_sample_type.md
index 5d38b67..fa0ed8c 100644
--- a/docs/test_sample_type.md
+++ b/docs/test_sample_type.md
@@ -12,7 +12,7 @@ getObject predicate: http://www.w3.org/2004/02/skos/core#prefLabel
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94df6cfdd0>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe13878d040>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -27,7 +27,7 @@ getObject predicate: http://purl.org/dc/terms/modified
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94df750770>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1395703e0>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -42,7 +42,7 @@ getObject predicate: http://www.w3.org/2004/02/skos/core#definition
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94de699160>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1384b9970>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -57,7 +57,7 @@ getObject predicate: http://www.w3.org/2000/01/rdf-schema#comment
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94df751160>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1395707a0>
 
 getObject prefixes: 
 PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
@@ -72,7 +72,7 @@ getObject predicate: http://www.w3.org/2004/02/skos/core#historyNote
 
 length of qres: 0
 
-qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7f94de698350>
+qres: <rdflib.plugins.sparql.processor.SPARQLResult object at 0x7fe1384ba2a0>
 
 ---
 comment: |