Python Arcade Styled Button

Programm says when running :

 font_name = style.get("font_name", UIFlatButton.UIStyle.font_name)
                ^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'get'

This shouldn't occur when using arcade I tried different code from the internet and the styling worked. But it doesn't work for me. Here is my code because I think it has to do with my code structure? please if anybody finds a reason it doesn't work tell me, I tried so much stuff and just don't understand the problem

#Module importieren
import arcade
import arcade.gui
import arcade.gui.widgets.buttons
import arcade.gui.widgets.layout
from arcade.gui import UIFlatButton

#Variablen definieren
width = 1200
height = 800
title = "Black Jack Arcade"
button_words = ["Hit", "Stand", "Split", "Double Down"]

border_color = arcade.color.ZINNWALDITE_BROWN

# Constants for sizing
CARD_SCALE = 0.6

# How big are the cards?
CARD_WIDTH = 140 * CARD_SCALE
CARD_HEIGHT = 190 * CARD_SCALE

# How big is the mat we'll place the card on?
MAT_PERCENT_OVERSIZE = 1.25
MAT_HEIGHT = int(CARD_HEIGHT * MAT_PERCENT_OVERSIZE)
MAT_WIDTH = int(CARD_WIDTH * MAT_PERCENT_OVERSIZE)

# How much space do we leave as a gap between the mats?
# Done as a percent of the mat size.
VERTICAL_MARGIN_PERCENT = 0.10
HORIZONTAL_MARGIN_PERCENT = 0.10

# The Y of the bottom row (2 piles)
BOTTOM_Y = MAT_HEIGHT / 2 + MAT_HEIGHT * VERTICAL_MARGIN_PERCENT

# The X of where to start putting things on the left side
START_X = MAT_WIDTH / 2 + MAT_WIDTH * HORIZONTAL_MARGIN_PERCENT

# Card constants
CARD_VALUES = ["A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K"]
CARD_SUITS = ["Kreuz", "Herz", "Pik", "Karo"]

#klassen erstellen

class graphic(arcade.Window):
    def __init__(self):
        super().__init__(width, height, title)
        #Initialisierung anderer Module
        self.ui = arcade.gui.UIManager()
        self.ui.enable()

        #startet die Buttons
        self.create_click()

        arcade.set_background_color(arcade.color.AO)



    # Hier werden alle externen Texturen geladen und eingesetzt
    def load_textures(self):
        # create wooden background
        wood_back = arcade.load_texture("/Users/maximilianstriegler/Desktop/Golden Black Jack/game_textures/background_wood.jpg")
        arcade.draw_lbwh_rectangle_textured(0, 0, 1200, 800, wood_back)

        # create green felt texture
        playing_field = arcade.load_texture("/Users/maximilianstriegler/Desktop/Golden Black Jack/game_textures/background_felt.jpg")
        arcade.draw_lbwh_rectangle_textured(250, 50, 900, 700, playing_field)
        arcade.draw_rectangle_outline(700, 400, 900, 700, border_color, 3)


    # Funktion um Knöpfe zu erstellen
    def create_button(self, x, y, width, height, color, border_width):
        arcade.draw_xywh_rectangle_filled(x - width / 2, y - height / 2, width, height, color)
        arcade.draw_rectangle_outline(x, y, width, height, border_color, border_width)


    def create_click(self):
        button_style = {
            "big" : UIFlatButton.UIStyle(
               font_size=20,
                font_name=('calibri', 'arial'),
                font_color=arcade.color.RED,
                bg=arcade.color.BLUE,
                border=arcade.color.BLUE,
                border_width=2,
            )
        }
        #create buttons
        for i in range(len(button_words)):
            buttons = arcade.gui.UIFlatButton(text=button_words[i], x=30, y=630 - (i * 150), width=190, height=100,
                                              style=button_style)

            buttons.on_click = self.on_click_button

            self.ui.add(buttons)


        exit_button = arcade.gui.UIFlatButton(text= "Exit", x= 77.5, y= 70, width= 95, height=50)
        exit_button.on_click = self.on_exit_quit

        self.ui.add(exit_button)


    #Funktion große Buttons
    def on_click_button(self, event):

            print("JAAAAA")


    #Funktion Exit Button
    def on_exit_quit(self, event):
        print("Exit Button Clicked")


    def on_draw(self):

        #Rendern starten
        arcade.start_render()

        #Texturen laden
        self.load_textures()

        #Buttons laden
        self.ui.draw()


        #Rendern beenden
        arcade.finish_render()


def start():
    window = graphic()
    arcade.run()

if __name__ == "__main__":
    start()

I was expecting the button to be styled but it wasn't. Not even my prof could help me with this problem and this dudes programming AI and stuff like that.

You're incorrectly defined button_style. Instead of big style you need to define normal, hover and press styles. Look at the fixed code:

import arcade
import arcade.gui
import arcade.gui.widgets.buttons
import arcade.gui.widgets.layout
from arcade.gui import UIFlatButton

BUTTON_WORDS = ['Hit', 'Stand', 'Split', 'Double Down']


class Graphic(arcade.Window):
    def __init__(self):
        super().__init__(title='Black Jack Arcade')
        self.ui = arcade.gui.UIManager()
        self.v_box = arcade.gui.widgets.layout.UIBoxLayout(space_between=20)
        ui_anchor_layout = arcade.gui.widgets.layout.UIAnchorLayout()
        ui_anchor_layout.add(child=self.v_box, anchor_x='center_x', anchor_y='center_y')
        button_style = {
            'normal': UIFlatButton.UIStyle(
                font_size=12,
                font_name=('calibri', 'arial'),
                font_color=arcade.color.WHITE,
                bg=arcade.color.RED,
                border=None,
                border_width=0,
            ),
            'hover': UIFlatButton.UIStyle(
                font_size=12,
                font_name=('calibri', 'arial'),
                font_color=arcade.color.WHITE,
                bg=arcade.color.REDWOOD,
                border=arcade.color.RED,
                border_width=2,
            ),
            'press': UIFlatButton.UIStyle(
                font_size=12,
                font_name=('calibri', 'arial'),
                font_color=arcade.color.WHITE,
                bg=arcade.color.RED_BROWN,
                border=arcade.color.REDWOOD,
                border_width=2,
            )
        }
        for i in range(len(BUTTON_WORDS)):
            buttons = arcade.gui.UIFlatButton(text=BUTTON_WORDS[i], x=30, y=630 - (i * 150), width=190, height=100, style=button_style)
            buttons.on_click = self.on_click_button
            self.v_box.add(buttons)
        exit_button = arcade.gui.UIFlatButton(text='Exit', x=77.5, y=70, width=95, height=50)
        exit_button.on_click = self.on_exit_quit
        self.ui.add(exit_button)
        self.ui.add(ui_anchor_layout)
        self.ui.enable()
        arcade.set_background_color(arcade.color.AO)

    def on_click_button(self, event):
        print('JAAAAA')

    def on_exit_quit(self, event):
        print('Exit Button Clicked')

    def on_draw(self):
        self.clear()
        self.ui.draw()


Graphic()
arcade.run()