def set_contrast(self, contrast):
if contrast < <NUM_LIT:0> or contrast > <NUM_LIT:255>:<EOL><INDENT>raise ValueError('<STR_LIT>')<EOL><DEDENT>self.command(SSD1306_SETCONTRAST)<EOL>self.command(contrast)<EOL>
Sets the contrast of the display.  Contrast should be a value between
        0 and 255.