No symbol found for field of field

Consider the following code snippet:
```python
class Bar:
    pass

class Foo:
    def __init__(self):
        self.bar = Bar()
        self.bar.baz = 9

foo = Foo()
baz = foo.bar.baz
```

SourcetrailPythonIndexer is unable to resolve the symbol `baz` in the last line of the snippet.

Tested with version `v0.db23.p2`