[Python] Why is lambda required in the else statement? [duplicate]

import tkinter as tk

def press(x):
entry.insert(tk.END, x)

def clear():
entry.delete(0, tk.END)

def calculate():
try:
result = eval(entry.get())
entry.delete(0, tk.END)
entry.insert(tk.END, str(result))
except Exception as e:
entry.delete(0, tk.END)
entry.insert(tk.END, "Error")

# Create main window
root = tk.Tk()

root.title("Simple Calculator")

# Display
entry = tk.Entry(root, width=30, font=("Arial", 18), bd=5, justify="right")

entry.grid(row=0, column=0, columnspan=4, padx=50, pady=10)

buttons = [('7', 1, 0), ('8', 1, 1), ('9', 1, 2), ('/', 1, 3), ('0', 4, 0),
('.', 4, 1), ('+', 4, 2), ('=', 4, 3),]

for (text, row, col) in buttons:
if text == '=':
cmd = calculate
else:
cmd = press(x)


tk.Button(root, text=text, width=5, height=2,command=cmd).grid(row=row, column=col)


# Clear button
tk.Button(root, text='C', width=22, height=2, font=("Arial", 18), command=clear).grid(row=5, column=0, columnspan=4)

root.mainloop()



I am trying to write a simple calculator with GUI. ChatGPT is saying I should use the lambda function in the else statement to get cmd = lambda x=textress(x) but I don't understand why. I wanted to assign the function press(x) to cmd so that later when I click the button, it will run whatever function is in the cmd but it seems like the lambda function is required to "wrap it" in a function.

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