I am getting an error in the following code

class finance_tracker:
    def __init__(self, root):
        self.root = root
        self.root.geometry("1000x550")
        self.root.resizable(False, False)
        self.root.title('Personal Finance Tracker')
        self.root.iconbitmap(r'C:UsersUSERDesktopSD1_CourseworksCOURSEWORK_03tracker_icon.ico')
        self.FILE_PATH = 'transaction.json'
        self.transactions = self.load_transaction()
        self.create_widgets()
        self.max_id = max(
            transaction['id'] for category in self.transactions.values() for transaction in
            category) if self.transactions else 0
        self.search_transactions()

    def create_widgets(self):

        # create label
        display_title = tk.Label(self.root, text="Manage Your Transactions Here!",
                                 anchor="center", font=TITLE_FONT_STYLE, bg=BLUE_GRAY)
        display_title.pack()

        # Add Some style
        style = ttk.Style()

        # pick a theme
        style.theme_use('clam')  # themes - defaults, alt, clam, vista

        # configure our treeview colors
        style.configure('Treeview',
                        background='White',
                        foreground='Black',
                        rowheight=25,
                        fieldbackground=ASH_GRAY)
        # change selected color
        style.map('Treeview',
                  background=[('selected', BUTTERSCOTCH_ORANGE)])

        # create treeview frame
        tree_frame = tk.Frame(self.root)
        tree_frame.configure(bg=BLUE_GRAY)
        tree_frame.pack(fill=tk.BOTH, expand=True, pady=10)

        # create treeview scroll bar
        tree_scroll = tk.Scrollbar(tree_frame)
        tree_scroll.configure(bg=BLUE_GRAY, relief=tk.FLAT)
        tree_scroll.pack(side=tk.RIGHT, fill=tk.Y)

        # create the tree view
        self.my_tree = ttk.Treeview(tree_frame, yscrollcommand=tree_scroll.set, selectmode=tk.EXTENDED)
        self.my_tree.pack(fill=tk.BOTH, padx=10)

        # defining columns
        self.my_tree['columns'] = (
            'Transaction Type', 'Transaction Category', 'Transaction Amount', 'Transaction Date', 'Transaction ID')

        # configure scroll bars
        tree_scroll.configure(command=self.my_tree.yview)

        # format columns
        self.my_tree.column('#0', width=0, stretch=NO)
        for col in self.my_tree['columns']:
            self.my_tree.column(col, anchor=tk.CENTER, width=120)

        # create headings
        self.my_tree.heading('#0', text='', anchor=tk.W)
        for col in self.my_tree['columns']:
            self.my_tree.heading(col, text=col, anchor=tk.CENTER,
                                 command=lambda col: self.sort_by_column(self.my_tree, col, False))

        # create transaction type based striped row tags
        self.my_tree.tag_configure('income_row', background=ROBIN_EGG_BLUE)
        self.my_tree.tag_configure('expense_row', background=VERDIGRIS_BLUE)

        # adding data to the screen
        self.count = 0
        for item in self.transactions.keys():
            for record in self.transactions.get(item):
                if record['type'] == 'Income':
                    self.my_tree.insert(parent='', index='end', iid=self.count, text='',
                                        values=(
                                        record['type'], item, f'{record['amount']:,.2f}', record['date'], record['id']),
                                        tags=('income_row',))
                elif record['type'] == 'Expense':
                    self.my_tree.insert(parent='', index='end', iid=self.count, text='',
                                        values=(
                                        record['type'], item, f'{record['amount']:,.2f}', record['date'], record['id']),
                                        tags=('expense_row',))
                self.count += 1  # increment counter
    def sort_by_column(self, tree, col, reverse):
        for row in tree.get_children():
            data = (tree.set(row, col), row)
            data.sort(reverse=reverse)

            for index in range(len(data)):
                val, row = data[index]
                tree.move(row, '', index)

            tree.heading(col, command=lambda c=col: self.sort_by_column(tree, c, not reverse))

I tried changing the code by changing c=col. But it did not worked