input: Write a python function to simulate a basic calculator with addition functionality using Tkinter.
  assert calculator_simulator('1+1=') == '2.0'
  assert calculator_simulator('2+2=') == '4.0'
  assert calculator_simulator('10+15=') == '25.0'
output: import tkinter as tk
  
  def calculator_simulator(expression):
      root = tk.Tk()
      root.withdraw()
      try:
          result = eval(expression.strip('='))
          return str(float(result))
      except Exception as e:
          return "Error"
      finally:
          root.destroy()