from typing import Tuple


def train_val_size(dataset, val_ratio: float = 0.1) -> Tuple[int, int]:
    """
    Return the train and validation data sizes based on split ratio.

    Args:
        dataset: A python collection
        val_ratio: Ratio for validation dataset

    Returns:
        Tuple of number of rows for (training, validation)
    """
    val_size = int(val_ratio * len(dataset))
    train_size = len(dataset) - val_size
    return train_size, val_size