diff --git a/owlapy/owl_ontology.py b/owlapy/owl_ontology.py
index 5f400401..fc4cd5eb 100644
--- a/owlapy/owl_ontology.py
+++ b/owlapy/owl_ontology.py
@@ -826,17 +826,18 @@ def properties_in_signature(self) -> Iterable[OWLProperty]:
     def individuals_in_signature(self) -> Iterable[OWLNamedIndividual]:
         for i in self._onto.individuals():
             yield OWLNamedIndividual(IRI.create(i.iri))
-
-    def tbox_axioms(self)->Iterable:
+    def get_abox_axioms(self)->Iterable:
+        # @TODO: CD: Return all information between owl classes, e.g. subclass or disjoint
+        raise NotImplementedError("will be implemented in future")
+    def get_tbox_axioms(self)->Iterable:
         # @TODO: CD: Return all information between owl classes, e.g. subclass or disjoint
         raise NotImplementedError("will be implemented in future")
-    def abox_axioms_between_individuals(self)->Iterable:
+    def get_abox_axioms_between_individuals(self)->Iterable:
         # @TODO: CD: Return all information between owl_individuals, i.e., triples with object properties
         raise NotImplementedError("will be implemented in future")
-    def abox_axioms_between_individuals_and_classes(self)->Iterable:
+    def get_abox_axioms_between_individuals_and_classes(self)->Iterable:
         # @TODO: CD: Return all type information about individuals, i.e., individual type Class
         raise NotImplementedError("will be implemented in future")
-
     # @TODO:CD:Unsure it is working
     def equivalent_classes_axioms(self, c: OWLClass) -> Iterable[OWLEquivalentClassesAxiom]:
         c_x: owlready2.ThingClass = self._world[c.str]
@@ -1019,6 +1020,9 @@ def __repr__(self):
                 f'\t|Data Properties|={len(self.data_properties_in_signature())}'
                 f'\n{self.manager}\tPath:{self.path}\tNew:{self.new}')
 
+    def __len__(self):
+        return len([i for i in self.get_abox_axioms()] + [i for i in self.get_abox_axioms()])
+
     def classes_in_signature(self) -> Iterable[OWLClass]:
         return self.mapper.map_(self.owlapi_ontology.getClassesInSignature())
 
@@ -1056,6 +1060,7 @@ def _get_imports_enum(self, include_imports_closure: bool):
         else:
             imports = Imports.EXCLUDED
         return imports
+
     def get_signature(self, include_imports_closure: bool = True):
         """Gets the entities that are in the signature of this ontology.
 
@@ -1065,8 +1070,6 @@ def get_signature(self, include_imports_closure: bool = True):
         Returns:
             Entities in signature.
         """
-        # @TODO: CD: Is this class method redundant given that we have the individuals_in_signature ?
-        # AB re: This method does not return only individuals.
         return self.mapper.map_(self.owlapi_ontology.getSignature(self._get_imports_enum(include_imports_closure)))
 
     def get_abox_axioms(self, include_imports_closure: bool = True) -> Iterable[OWLAxiom]:
diff --git a/tests/test_sync_ontology_read_write.py b/tests/test_sync_ontology_read_write.py
new file mode 100644
index 00000000..43c1beb0
--- /dev/null
+++ b/tests/test_sync_ontology_read_write.py
@@ -0,0 +1,23 @@
+import unittest
+from owlapy.owl_ontology_manager import SyncOntologyManager, OntologyManager
+
+
+
+class TestSyncReasoner(unittest.TestCase):
+    def test_read_write(self):
+        # Create an empty ontology
+        o1 = SyncOntologyManager().create_ontology("file:/example_ontology.owl")
+        # () Add tbox axioms from another ontology
+        for axiom in SyncOntologyManager().load_ontology("KGs/Family/father.owl").get_tbox_axioms():
+            o1.add_axiom(axiom)
+        # () Add abox axioms from another ontology
+        for axiom in SyncOntologyManager().load_ontology("KGs/Family/father.owl").get_abox_axioms():
+            o1.add_axiom(axiom)
+        o1.save(path="demo.owl")
+        # Check the axiom numbers
+        abox = len([i for i in o1.get_abox_axioms()])
+        tbox = len([i for i in o1.get_tbox_axioms()])
+
+        o2 = SyncOntologyManager().load_ontology(path="demo.owl")
+        assert abox == len([i for i in o2.get_abox_axioms()])
+        assert tbox == len([i for i in o2.get_tbox_axioms()])
\ No newline at end of file