input: Write a function to create a simple GUI email client using tkinter.
  assert "From:" in create_email_client()
  assert "To:" in create_email_client()
  assert "Subject:" in create_email_client()
  assert "Body:" in create_email_client()
output: def create_email_client():
      import tkinter as tk
      from tkinter import messagebox
  
      def send_email():
          from_email = from_entry.get()
          to_email = to_entry.get()
          subject = subject_entry.get()
          body = body_text.get("1.0", tk.END)
          messagebox.showinfo("Email Sent", f"From: {from_email}\nTo: {to_email}\nSubject: {subject}\nBody: {body}")
  
      root = tk.Tk()
      root.title("Simple Email Client")
  
      tk.Label(root, text="From:").grid(row=0, column=0)
      from_entry = tk.Entry(root)
      from_entry.grid(row=0, column=1)
  
      tk.Label(root, text="To:").grid(row=1, column=0)
      to_entry = tk.Entry(root)
      to_entry.grid(row=1, column=1)
  
      tk.Label(root, text="Subject:").grid(row=2, column=0)
      subject_entry = tk.Entry(root)
      subject_entry.grid(row=2, column=1)
  
      tk.Label(root, text="Body:").grid(row=3, column=0)
      body_text = tk.Text(root, height=10, width=30)
      body_text.grid(row=3, column=1)
  
      send_button = tk.Button(root, text="Send", command=send_email)
      send_button.grid(row=4, column=1)
  
      root.mainloop()