Created a method that emulates isinsntace for aggregation

This will allow us to check if something wrapped with dask is "checkpointable", or "samplable" or something else

bob/pipelines/tests/test_utils.py

@@ -116,3 +116,26 @@ def test_io_vstack():
             finally:
                 # create the file back so NamedTemporaryFile does not complain
                 np.save(paths[0], reader(i + 1))
+
+def test_isinstance_nested():
+
+    class A:
+        pass
+
+    class B:
+        def __init__(self, o):
+            self.o = o
+
+    class C:
+        def __init__(self, o):
+            self.o = o
+
+    o = C(B(A()))
+    assert mario.utils.isinstance_nested(o, "o", C)
+    assert mario.utils.isinstance_nested(o, "o", B)
+    assert mario.utils.isinstance_nested(o, "o", A)
+
+    o = C(B(object))
+    assert mario.utils.isinstance_nested(o, "o", C)
+    assert mario.utils.isinstance_nested(o, "o", B)
+    assert not mario.utils.isinstance_nested(o, "o", A)