
    Given a binary security flag for a banking transaction where each bit represents a security check status (0 for unchecked, 1 for checked), write a function that identifies and sets the leftmost unchecked security measure to 'checked' status. This enhancement helps strengthen transaction security by ensuring the highest-priority remaining security check is activated.
    

    
def set_left_most_unset_bit(n):
    """
    Given a binary security flag for a banking transaction where each bit represents a security check status (0 for unchecked, 1 for checked), write a function that identifies and sets the leftmost unchecked security measure to 'checked' status. This enhancement helps strengthen transaction security by ensuring the highest-priority remaining security check is activated.
    

    """
def set_left_most_unset_bit(n):
    """
    Given a binary security flag for a banking transaction where each bit represents a security check status (0 for unchecked, 1 for checked), write a function that identifies and sets the leftmost unchecked security measure to 'checked' status. This enhancement helps strengthen transaction security by ensuring the highest-priority remaining security check is activated.
    

    """
    if not n & n + 1:
        return n
    (pos, temp, count) = (0, n, 0)
    while temp:
        if not temp & 1:
            pos = count
        count += 1
        temp >>= 1
    return n | 1 << pos