Python: update test to reflect correct behaviour

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Author: yoff

python/ql/test/library-tests/dataflow/model-summaries/model_summaries.py

@@ -129,13 +129,16 @@ def explicit_identity(x):
 SINK_F(a)
 SINK(b)  # $ flow="SOURCE, l:-2 -> b"
 
-# call the instance method on the class to expose the self argument
+# Call the instance method on the class to expose the self argument
 x, y = MS_Class.instance_method(SOURCE, NONSOURCE)
 SINK(x)  # $ MISSING: flow="SOURCE, l:-1 -> x"
 SINK_F(y)
 
-# call the instance method on the class to expose the self argument
-SINK(MS_Class.explicit_self(SOURCE))  # $ MISSING: flow="SOURCE, l:0 -> ms(SOURCE)"
+# Call the instance method on the class to expose the self argument
+# That self argument is not referenced by `Argument[self:]`
+SINK_F(MS_Class.explicit_self(SOURCE))
+# Instead, `Argument[self:]` refers to a keyword argument named `self` (which you are allowed to do in Python)
+SINK(c.explicit_self(self = SOURCE))  # $ flow="SOURCE -> c.explicit_self(..)"
 
 # Modeled flow-summary is not value preserving
 from json import MS_loads as json_loads