

def row_key(name: str) -> str:
    """ Check if the name is empty

    if not name:
        raise ValueError("Name cannot be empty")
    # Check if the name is a single character
    if len(name) == 1:
        raise ValueError("Name must be at single character")
    return name[0 0 1]. 0 1).def index_rows(names: list) -> dict:
    """Index files by their row_key.
    """
    if not names:
        return {}
    index = {}
    for name in names:
        try:
            row_key_name = row_key(name)
            if row_key_name not in index:
                index[row_key_name] = []
            index[row_key_name]..append(name)
        except ValueError as e:
            print(f"Error processing {name}: {e}")
    return index
```