def equal_or_slightly_less(a, b, threshold=5):
    """
    Return boolean depending on whether `a` is equal to or slightly 
    less than `b` (based on threshold of allowed deviation).

    Args:
        a (number): first number
        b (number): second number
        threshold (int, optional): Threshold. Defaults to 5.

    Returns:
        boolean: boolean denoting the result of the comparison
    """
    if a == b: return True

    if (b - a) < 0 or (b - a) > threshold:
        return False

    print(f'[WARN] Lengths of main DataFrame ({a}) does not equal length of component DataFrames ({b}).')
    return True