

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:
    """ Return a dictionary where the row_key function """
    index = {}
    for name in names:
        try:
            row = row_key(name)
            index[row] = index.get(row, []) + [name]
 except ValueError as e:
            print(f"Erroring {name} as it does not start with a letter: {str(e)}")
    return index
```