How to use the keymapviz.keyboards.ergo42 function in keymapviz

import keymapviz.keyboards.crkbd
import keymapviz.keyboards.ergo42
import keymapviz.keyboards.ergodash
import keymapviz.keyboards.ergodox
import keymapviz.keyboards.fortitude60
import keymapviz.keyboards.lets_split
import keymapviz.keyboards.kinesis
import keymapviz.keyboards.helix
import keymapviz.keyboards.mint60
import keymapviz.keyboards.kaishi65


KEYBOARDS = {
    'crkbd': keymapviz.keyboards.crkbd,
    'ergo42': keymapviz.keyboards.ergo42,
    'ergodash': keymapviz.keyboards.ergodash,
    'ergodox': keymapviz.keyboards.ergodox,
    'ergodox_ez': keymapviz.keyboards.ergodox,
    'fortitude60': keymapviz.keyboards.fortitude60,
    'helix': keymapviz.keyboards.helix,
    'kinesis': keymapviz.keyboards.kinesis,
    'lets_split': keymapviz.keyboards.lets_split,
    'mint60': keymapviz.keyboards.mint60,
    'kaishi65': keymapviz.keyboards.kaishi65
}


class Keymapviz():
    def __init__(self, keyboard, keymap_c, legends = None):
        self.__keymap_c = keymap_c.read()
        self.keyboard = KEYBOARDS[keyboard]