```python
from typing import Dict

def add_one(tally: Dict[str, int], name:       if name not in tally:
        raise ValueError("Name not found in tally")
    return {**        **tally,
        name:        tally[name] + 1
    }

def merge_tally(left:    right):
    return {
        **left,
        **right,
        key: left.get(key,            right.get(key,                left[key] + right[key]
            else[key]:
    }
}
```