def get_smallest_prime_factor(n):
    """
    Returns the smallest integer that is a factor of `n`.
    
    If `n` is a prime number `None` is returned.

    Parameters
    ----------
    n : int
        The integer to be factored.

    Returns
    -------
    int or None
        The smallest integer that is a factor of `n`
        or None if `n` is a prime.
    Examples
    --------
    >>> get_smallest_prime_factor(7)
    >>> get_smallest_prime_factor(8)
    2
    >>> get_smallest_prime_factor(9)
    3
    """
    for i in range(2, n):
        if (n % i) == 0:
            return i
    return None