code: public static DataPropertyAssertion createDataPropertyAssertion(DataPropertyExpression dpe, ObjectConstant o1, ValueConstant o2) throws InconsistentOntologyException {
          if (dpe.isTop())
              return null;
          if (dpe.isBottom())
              throw new InconsistentOntologyException();
  
          return new DataPropertyAssertionImpl(dpe, o1, o2);
      }
docs: Creates a data property assertion
  <p>
  DataPropertyAssertion := 'DataPropertyAssertion' '(' axiomAnnotations
  DataPropertyExpression sourceIndividual targetValue ')'
  <p>
  Implements rule [D4]:
  - ignore (return null) if the property is top
  - inconsistency if the property is bot