False Negative - Python `abc.ABC` makes method's `getACall` unavailable

If we have this Python code:
```python
class MyClass():
def method(self):
print("xxx")
def wrapper(self):
self.method()

mc = MyClass()
mc.method()
```
and this query:
```codeql
import python

from PythonFunctionValue method
select method.getACall()
```
It's OK that `self.method()` and `mc.method()` will be marked as positive.

However, those will be false negative as long as the class `MyClass` inherits `abc.ABC`. It looks like:
```python
from abc import ABC

class MyClass(ABC):
def method(self):
print("xxx")
def wrapper(self):
self.method()

mc = MyClass()
mc.method()
```

Why does the `abc.ABC` make the result wrong?

Reproduce the two Python examples and run the shown CodeQL query importing PythonFunctionValue. Compare whether getACall() reports method calls with and without abc.ABC inheritance, then inspect the Python library behavior responsible for the difference. Done means the query consistently recognizes the calls in both examples or the issue documents the supported limitation.

Scritto dal modello di indicizzazione a partire dal testo della issue.