[SIM121] Use ".get" instead of "if X in dict: dict[X]"

## Explanation

The `get(key, default_fallback=None)` method of a dictionary is often overlooked. It provides a clear interface that every Python developer should know.

## Example

```python
# Bad
name = "some_default"
if "some_key" in some_dict:
    name = some_dict["some_key"]

# Good
name = some_dict.get("some_key", "some_default")
```
