Не работает функция insert sqlite

from tkinter import *
from tkinter import ttk
import sqlite3
 
conn = sqlite3.connect('finance.db')
c = conn.cursor()
c.execute('''CREATE TABLE IF NOT EXISTS finance (id int auto_increment, description text, costs text, sum real, date text)''')
 
class main:
    def __init__(self, master):
        self.master = master
        self.master.title('Домашние финансы')
        self.master.geometry('650x400+300+200')
 
        toolbar = Frame(master)
        toolbar.pack(side=TOP, fill=X)
        toolbar.config(bg='#d7d8e0', bd=2)
 
        self.add_img = PhotoImage(file="add.gif")
        self.btnOpenDialog = Button(toolbar, text='Добавить позицию', command=self.openDialog, image=self.add_img)
        self.btnOpenDialog.pack(side=LEFT)
        self.btnOpenDialog.config(bg='#d7d8e0', bd=0, compound=TOP)
 
        self.master.mainloop()
 
    def openDialog(self):
        child(self.master)
 
 
class child:
    def __init__(self, master):
        self.slave = Toplevel(master)
        self.slave.title('Добавить доходы/расходы')
        self.slave.geometry('400x220+400+300')
        self.slave.resizable(False, False)
 
        self.labelDescription = Label(self.slave, text='Наименование:')
        self.labelDescription.place(x=50, y=50)
        self.labelSelect = Label(self.slave, text='Статья дохода/расхода:')
        self.labelSelect.place(x=50, y=80)
        self.labelSum = Label(self.slave, text='Сумма:')
        self.labelSum.place(x=50, y=110)
 
        self.entryDescription = ttk.Entry(self.slave)
        self.entryDescription.place(x=200, y=50)
 
        self.entryMoney = ttk.Entry(self.slave)
        self.entryMoney.place(x=200, y=110)
 
        self.combobox = ttk.Combobox(self.slave, values=[u"Доход", u"Расход"])
        self.combobox.place(x=200, y=80)
 
        self.btnCancel = ttk.Button(self.slave, text='Отмена')
        self.btnCancel.place(x=300, y=170)
 
        self.btnOk = ttk.Button(self.slave, text='OK')
        self.btnOk.place(x=220, y=170)
        self.btnOk.bind('<Button-1>', lambda event: self.insertData(str(self.entryDescription.get()),
                                                                    str(self.combobox.get()),
                                                                    float(self.entryMoney.get())))
 
        self.slave.grab_set()
        self.slave.focus_set()
        self.slave.wait_window()
 
    def insertData(self, description, costs, sum):
        c.execute('''INSERT INTO finance(description, costs, sum) VALUES (?, ?, ?)''', description, costs, sum)
        conn.commit()
        conn.close()
 
root = Tk()
 
main(root)

child().insertData()

C:\Python35\python.exe C:/Users/DANNY/PycharmProjects/test/test.py
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python35\lib\tkinter\__init__.py", line 1559, in __call__
    return self.func(*args)
  File "C:/Users/DANNY/PycharmProjects/test/test.py", line 60, in <lambda>
    float(self.entryMoney.get())))
ValueError: could not convert string to float: 
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python35\lib\tkinter\__init__.py", line 1559, in __call__
    return self.func(*args)
  File "C:/Users/DANNY/PycharmProjects/test/test.py", line 60, in <lambda>
    float(self.entryMoney.get())))
  File "C:/Users/DANNY/PycharmProjects/test/test.py", line 67, in insertData
    c.execute('''INSERT INTO finance(description, costs, sum) VALUES (?, ?, ?)''', description, costs, sum)
TypeError: function takes at most 2 arguments (4 given)
 
Process finished with exit code 0

c.execute('''INSERT INTO finance(description, costs, sum) VALUES (?, ?, ?)''', (description, costs, sum))

sum