``import mathfrom typing import Tuplefrom h2o_wave import Q, app, data, main, uidef to_grayscale(color: float) -> float:    color /= 255    return color / 12.92 if color <= 0.03928 else math.pow((color + 0.055) / 1.055, 2.4)def get_luminance(r: float, g: float, b: float) -> float:    return to_grayscale(r) * 0.2126 + to_grayscale(g) * 0.7152 + to_grayscale(b) * 0.0722# Source: https://www.delftstack.com/howto/python/python-hex-to-rgb/.def hex_to_rgb(hex_color: str) -> Tuple[int, ...]:    if len(hex_color) == 3:        hex_color = f'{hex_color[0]}{hex_color[0]}{hex_color[1]}{hex_color[1]}{hex_color[2]}{hex_color[2]}'    return tuple(int(hex_color[i:i + 2], 16) for i in (0, 2, 4))# Source: https://stackoverflow.com/questions/9733288/how-to-programmatically-calculate-the-contrast-ratio-between-two-colors. # noqadef update_contrast_check(color1: str, color2: str, q: Q, min_contrast=4.5):    rgb1 = hex_to_rgb(q.client[color1].lstrip('#'))    rgb2 = hex_to_rgb(q.client[color2].lstrip('#'))    lum1 = get_luminance(rgb1[0], rgb1[1], rgb1[2])    lum2 = get_luminance(rgb2[0], rgb2[1], rgb2[2])    brightest = max(lum1, lum2)    darkest = min(lum1, lum2)    contrast = (brightest + 0.05) / (darkest + 0.05)    message_bar_mobile = q.page['meta'][f'{color1}_{color2}']    message_bar = q.page['form'][f'{color1}_{color2}']    if contrast < min_contrast:        message_bar.type = message_bar_mobile.type = 'error'        message_bar.text = message_bar_mobile.text = f'Improve contrast between **{color1}** and **{color2}**.'    else:        message_bar.type = message_bar_mobile.type = 'success'        message_bar.text = message_bar_mobile.text = f'Contrast between **{color1}** and **{color2}** is great!'def get_theme_code(q: Q):    return f'''```pyui.theme(    name='<theme-name>',    primary='{q.client.primary}',    text='{q.client.text}',    card='{q.client.card}',    page='{q.client.page}',)'''image = 'https://images.pexels.com/photos/220453/pexels-photo-220453.jpeg?auto=compress&h=750&w=1260'mobile_items = [    ui.text_xl(content='Sample App to show colors'),    ui.text('Click the top right button to change the theme. ðŸ‘†'),    ui.inline(justify='between', items=[        ui.persona(title='John Doe', subtitle='Data Scientist', size='s', image=image),        ui.toggle(name='toggle', label='Toggle', value=True),    ]),    ui.inline([        ui.stepper(name='stepper', width='500px', items=[            ui.step(label='Step 1', icon='MailLowImportance'),            ui.step(label='Step 2', icon='TaskManagerMirrored'),            ui.step(label='Step 3', icon='Cafe'),        ]),    ]),    ui.progress(label='A progress bar'),    ui.inline(justify='between', items=[        ui.tabs(name='menu', value='email', items=[            ui.tab(name='email', label='Mail', icon='Mail'),            ui.tab(name='events', label='Events', icon='Calendar'),            ui.tab(name='spam', label='Spam'),        ]),        ui.link(label='Link'),    ]),    ui.slider(name='slider', label='Slider', value=70),    ui.date_picker(name='date_picker', label='Date picker'),    ui.picker(name='picker', label='Picker', choices=[        ui.choice('choice1', label='Choice 1'),        ui.choice('choice2', label='Choice 2'),        ui.choice('choice3', label='Choice 3'),    ]),    ui.combobox(name='combobox', label='Combobox', choices=['Choice 1', 'Choice 2', 'Choice 3']),    ui.checkbox(name='checkbox1', label='Checkbox 1', value=True),    ui.checkbox(name='checkbox2', label='Checkbox 2'),    ui.checkbox(name='checkbox3', label='Checkbox 3'),    ui.inline(direction='column', items=[        ui.table(            name='table',            width='100%',            columns=[                ui.table_column(name='name', label='Name', min_width='80px'),                ui.table_column(name='surname', label='Surname', filterable=True, max_width='90px'),                ui.table_column(name='progress', label='Progress', max_width='80px',                                cell_type=ui.progress_table_cell_type(color='\$themePrimary')),            ],            rows=[                ui.table_row(name='row1', cells=['John', 'Doe', '0.90']),                ui.table_row(name='row2', cells=['Ann', 'Doe', '0.75']),            ],        ),        ui.visualization(            width='100%',            data=data('profession salary', 5, rows=[                ('medicine', 23000),                ('fire fighting', 18000),                ('pedagogy', 24000),                ('psychology', 22500),                ('computer science', 36000),            ], pack=True),            plot=ui.plot([ui.mark(type='interval', x='=profession', y='=salary', y_min=0)])        ),    ]),    ui.buttons([        ui.button(name='primary_button', label='Primary', primary=True),        ui.button(name='standard_button', label='Standard'),        ui.button(name='standard_disabled_button', label='Disabled', disabled=True),        ui.button(name='icon_button', icon='Heart', caption='Tooltip text'),    ]),]desktop_items = [    ui.text_xl(content='Sample App to show colors'),    ui.progress(label='A progress bar'),    ui.inline([        ui.checkbox(name='checkbox1', label='Checkbox 1', value=True),        ui.checkbox(name='checkbox2', label='Checkbox 2'),        ui.checkbox(name='checkbox3', label='Checkbox 3'),        ui.toggle(name='toggle', label='Toggle', value=True),    ]),    ui.inline([        ui.date_picker(name='date_picker', label='Date picker'),        ui.picker(name='picker', label='Picker', choices=[            ui.choice('choice1', label='Choice 1'),            ui.choice('choice2', label='Choice 2'),            ui.choice('choice3', label='Choice 3'),        ]),        ui.combobox(name='combobox', label='Combobox', choices=['Choice 1', 'Choice 2', 'Choice 3']),        ui.persona(title='John Doe', subtitle='Data Scientist', size='s', image=image),    ]),    ui.slider(name='slider', label='Slider', value=70),    ui.link(label='Link'),    ui.inline(justify='between', items=[        ui.stepper(name='stepper', width='500px', items=[            ui.step(label='Step 1', icon='MailLowImportance'),            ui.step(label='Step 2', icon='TaskManagerMirrored'),            ui.step(label='Step 3', icon='Cafe'),        ]),        ui.tabs(name='menu', value='email', items=[            ui.tab(name='email', label='Mail', icon='Mail'),            ui.tab(name='events', label='Events', icon='Calendar'),            ui.tab(name='spam', label='Spam'),        ]),    ]),    ui.inline(items=[        ui.table(            name='table',            width='50%',            columns=[                ui.table_column(name='name', label='Name', min_width='80px'),                ui.table_column(name='surname', label='Surname', filterable=True),                ui.table_column(name='age', label='Age', sortable=True, max_width='80px'),                ui.table_column(name='progress', label='Progress',                                cell_type=ui.progress_table_cell_type(color='\$themePrimary')),            ],            rows=[                ui.table_row(name='row1', cells=['John', 'Doe', '25', '0.90']),                ui.table_row(name='row2', cells=['Ann', 'Doe', '35', '0.75']),                ui.table_row(name='row3', cells=['Casey', 'Smith', '40', '0.33']),            ],            height='330px',        ),        ui.visualization(            width='50%',            data=data('profession salary', 5, rows=[                ('medicine', 23000),                ('fire fighting', 18000),                ('pedagogy', 24000),                ('psychology', 22500),                ('computer science', 36000),            ], pack=True),            plot=ui.plot([ui.mark(type='interval', x='=profession', y='=salary', y_min=0)])        ),    ]),    ui.buttons([        ui.button(name='primary_button', label='Primary', primary=True),        ui.button(name='standard_button', label='Standard'),        ui.button(name='standard_disabled_button', label='Disabled', disabled=True),        ui.button(name='icon_button', icon='Heart', caption='Tooltip text'),    ]),]@app('/demo')async def serve(q: Q):    if not q.client.initialized:        q.client.primary = '#000000'        q.client.page = '#e2e2e2'        q.client.card = '#ffffff'        q.client.text = '#000000'        q.page['meta'] = ui.meta_card(box='', theme='custom', layouts=[            ui.layout(                breakpoint='xs',                zones=[                    ui.zone('mobile_content'),                    ui.zone('footer')                ]            ),            ui.layout(                breakpoint='817px',                zones=[                    ui.zone('header'),                    ui.zone('content', direction=ui.ZoneDirection.ROW, zones=[                        ui.zone('colors', size='30%'),                        ui.zone('preview', size='70%')                    ]),                    ui.zone('footer')                ]            ),        ])        q.page['header'] = ui.header_card(box='header', title='Theme generator', subtitle='Color your app easily',                                          icon='Color', icon_color='\$card')        q.page['mobile_header'] = ui.header_card(            box='mobile_content',            icon='Color',            title='Theme generator',            subtitle='Color your app easily',            items=[ui.button(name='show_side_panel', label=' ', icon='Color')]        )        q.client.color_items = [            ui.color_picker(name='primary', label='Primary', trigger=True, alpha=False, inline=True,                            value=q.client.primary),            ui.color_picker(name='text', label='Text', trigger=True, alpha=False, inline=True, value=q.client.text),            ui.color_picker(name='card', label='Card', trigger=True, alpha=False, inline=True, value=q.client.card),            ui.color_picker(name='page', label='Page', trigger=True, alpha=False, inline=True, value=q.client.page),            ui.text_xl('Check contrast'),            ui.message_bar(name='text_card', type='success', text='Contrast between **text** and **card** is great!'),            ui.message_bar(name='card_primary', type='success',                           text='Contrast between **card** and **primary** is great!'),            ui.message_bar(name='text_page', type='success', text='Contrast between **text** and **page** is great!'),            ui.message_bar(name='page_primary', type='success',                           text='Contrast between **page** and **primary** is great!'),            ui.text_xl('Copy code'),            ui.text(name='code', content=get_theme_code(q)),        ]        q.page['form'] = ui.form_card(box='colors', items=q.client.color_items)        q.page['sample'] = ui.form_card(box='preview', items=desktop_items)        q.page['sample_mobile'] = ui.form_card(box='mobile_content', items=mobile_items)        q.page['footer'] = ui.footer_card(box='footer', caption='Made with ðŸ’› by H2O Wave Team.')        q.client.themes = [ui.theme(name='custom', text=q.client.text, card=q.client.card,                                    page=q.client.page, primary=q.client.primary)]        q.client.initialized = True    if q.args.show_side_panel:        q.page['meta'].side_panel = ui.side_panel(            title='Adjust theme colors',            items=q.client.color_items,            closable=True,            width='min(75%, 420px)'        )    if q.args.primary:        q.client.themes[0].primary = q.args.primary        q.client.primary = q.args.primary    if q.args.text:        q.client.themes[0].text = q.args.text        q.client.text = q.args.text    if q.args.card:        q.client.themes[0].card = q.args.card        q.client.card = q.args.card    if q.args.page:        q.client.themes[0].page = q.args.page        q.client.page = q.args.page    q.page['meta'].themes = q.client.themes    update_contrast_check('text', 'card', q)    update_contrast_check('card', 'primary', q)    update_contrast_check('text', 'page', q)    update_contrast_check('page', 'primary', q)    q.page['form'].code.content = get_theme_code(q)    await q.page.save()``