def generate_optimized_y_move_down_x_SOL(y_dist):
    """ move down y_dist, set x=0 """

    # Optimization to move N lines and go to SOL in one command. Note that some terminals 
    # may not support this so we might have to remove this optimization or make it optional 
    # if that winds up mattering for terminals we care about. If we had to remove we'd
    # want to rework things such that we used "\x1b[{0}B" but also we would want to change
    # our interface to this function so we didn't guarantee x=0 since caller might ultimate 
    # want it in a different place and we don't want to output two x moves. Could pass in 
    # desired x, or return current x from here. 
          
    string = "\x1b[{0}E".format(y_dist)  # ANSI code to move down N lines and move x to SOL

    # Would a sequence of 1 or more \n chars be cheaper? If so we'll output that instead
    if y_dist < len(string):
        string = '\n' * y_dist
        
    return string
move down y_dist, set x=0