def in_region(pos, regions):
    """Find whether a position is included in a region.

    Parameters
    ----------
    pos : int
        DNA base position.
    regions : list of tuples
        List of (start, end) position integers.

    Returns
    -------
    bool
        True if the position is within an of the regions, False otherwise.

    Examples
    --------
    # Empty list
    >>> in_region(1, [])
    False

    # In list
    >>> in_region(10, [(3, 5), (9, 12)])
    True

    # Not in list
    >>> in_region(10, [(3, 5), (11, 12)])
    False
    """
    for region in regions:
        if pos >= region[0] and pos <= region[1]:
            return True
    return False
