def find_midpoint(low, high):
    """
    Find the midpoint between two numbers. Expects low <= high.

    Args:
        low (int): Low number
        high (int): High number

    Returns:
        (int): midpoint between low and high
    """
    if high < low:
        raise ValueError("Expected arg \"low\" to be less than arg \"high\"")

    return low + (high - low) / 2