def validate_string(data: str) -> bool:
    """
    Validate input for a field that must have a ``str`` value.

    Args:
        data (str): The data to be validated.

    Returns:
        bool: Validation passed.

    Raises:
        ValueError: Validation failed.
    """
    if not isinstance(data, str):
        raise ValueError(f"Not a string ({data})")
    return True