Sorry, I forgot to add if __name__ line:
```
import codegen
from dataclasses import dataclass

@dataclass
class AtomX:
    my_symbol: str
    quantity: str = ""


if __name__ == "__main__":
    codegen.inheritance_map(AtomX("qwerty"))

```

So the output:
```
Traceback (most recent call last):
  File "/Users/baskakov/PycharmProjects/main.py", line 11, in <module>
    codegen.inheritance_map(AtomX("qwerty"))
  File "/Users/baskakov/PycharmProjects/codegen.py", line 5, in inheritance_map
    assert isinstance(candidate, AtomX)
AssertionError

```