Makes sure the observer examples run (#245)

examples/observers/adding_an_mlflow_observer/example_logging_rdkit_logp_using_mlflow.py

@@ -29,12 +29,16 @@
     # Initializing a logP objective function.
     problem = objective_factory.create(
         name="rdkit_logp",
-        observer=observer,
         string_representation="SELFIES",
-        observer_init_info={"run_id": None, "experiment_id": None},
     )
     f, x0 = problem.black_box, problem.x0
 
+    # Attaching the observer to the black box
+    observer.initialize_observer(
+        f.info, caller_info={"run_id": None, "experiment_id": None}, seed=1
+    )
+    f.set_observer(observer)
+
     # Logging some examples
     # The observer will register each call to f.
     f(np.array([["[C]", "[C]"]]))