class ASCII:
    ETX = 3   # end of text (ctrl+c)
    EOT = 4   # end of transmission (ctrl+d)
    BS  = 8   # backspace
    TAB = 9   # horizontal tab
    LF  = 10  # line feed (new line)
    VT  = 11  # vertical tab
    FF  = 12  # form feed (new page)
    CR  = 13  # carriage return (enter)
    ESC = 27  # starts escape sequence
    DEL = 127 # backspace gives this

class ASCII:
    ETX = 3   # end of text (ctrl+c)
    EOT = 4   # end of transmission (ctrl+d)
    BS  = 8   # backspace
    TAB = 9   # horizontal tab
    LF  = 10  # line feed (new line)
    VT  = 11  # vertical tab
    FF  = 12  # form feed (new page)
    CR  = 13  # carriage return (enter)
    SUB = 26  # substitute ctrl+z
    ESC = 27  # starts escape sequence
    DEL = 127 # backspace gives this

Add ASCII code SUB