Why am I not allowed to use grid?

I am coding an app called eTasks. Below is the code for the window that shows when you want to create a new task:

import tkinter as tk 
from tkinter import ttk
from tkinter import*
from time import strftime
from datetime import date
from tkinter import messagebox
import TaskCls as ct
from TaskCls import task
import shelve
#import python_weather
import asyncio
import os
import quickbar as qb
from task_obj import nTask
import task_obj as nt
import pickle
import pyodbc
import pandas as pd

todohome=tk.Tk()
def newtaskwin():
    #window is shown when create task button is pressed.
    newtaskwin=Toplevel(todohome)
    newtaskwin.geometry()
    tasknameframe=tk.Frame(newtaskwin, relief='groove', highlightbackground='black', highlightthickness=1, width=250).grid()
    #task name box
    TaskNameLbl=tk.Label(tasknameframe, text='Task Name:').grid(row=1, column=0, pady=5)
    TaskNameEntry=ttk.Entry(tasknameframe, width=100)
    TaskNameEntry.grid(row=1, column=1, pady=5)
    #Group to put the task into
    GroupNameLbl=tk.Label(newtaskwin, text='Group:').grid(row=2, column=0, pady=5)
    GroupNameEntry=ttk.Entry(newtaskwin, width=100)
    GroupNameEntry.grid(row=2, column=1, pady=5)
    #importance of task
    PriorityLbl=tk.Label(newtaskwin, text='Priority:').grid(row=3, column=0, pady=5)
    PriorityEntry=ttk.Combobox(newtaskwin, state="readonly", values=['High', 'Medium', 'Low'], width=97)
    PriorityEntry.grid(row=3, column=1, pady=5)
    #date the task will start
    start_date_lbl=tk.Label(newtaskwin, text='Start Date:').grid(row=4, column=0, pady=5)
    start_date_entry=ttk.Entry(newtaskwin, width=100)
    start_date_entry.grid(row=4, column=1, pady=5)
    #date the task will end
    end_date_lbl=tk.Label(newtaskwin, text='End Date:').grid(row=5, column=0, pady=5)
    end_date_entry=ttk.Entry(newtaskwin, width=100)
    end_date_entry.grid(row=5, column=1, pady=5)
    #time you will start the task
    start_time_lbl=tk.Label(newtaskwin, text='Start Time:').grid(row=6, column=0, pady=5)
    start_time_entry=ttk.Entry(newtaskwin, width=100)
    start_time_entry.grid(row=6, column=1, pady=5)
    #time you will finish the task
    end_time_lbl=tk.Label(newtaskwin, text='End Time:').grid(row=7, column=0, pady=5)
    end_time_entry=ttk.Entry(newtaskwin, width=100)
    end_time_entry.grid(row=7, column=1, pady=5)
    slaves = newtaskwin.grid_slaves()
    print (f'grid slaves:{slaves}')

    def create_task():
        tName = TaskNameEntry.get()
        gName=GroupNameEntry.get()
        pName=PriorityEntry.get()
        sDate=start_date_entry.get()
        eDate=end_date_entry.get()
        sTime=start_time_entry.get()
        eTime=end_time_entry.get()
        conn=pyodbc.connect(r'Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=C:\Users\ellio_6\Documents\etasks-main\src\tasksdb.accdb')
        cursor=conn.cursor()
        sql="insert into TaskDB values ('{tName}', '{pName}', '{gName}', '{sDate}', '{eDate}', '{sTime}', '{eTime}')".format(
            tName='Task Name', pName='High', gName = 'Group Name', sDate = '14/03/23', eDate = '15/03/23', sTime = '17:48', eTime = '18:48')
        try:
            cursor.execute(sql)
            cursor.commit()
            new_tsk=nt.nTask(tName, sDate, eDate, mainfrme)
            new_tsk.pack(side=tk.TOP)
            messagebox.showinfo('eTasks', 'Task saved')
        except pyodbc.IntegrityError:
            messagebox.showinfo('eTasks', 'You already have a task with that name. Please change it.')

            
    #button to save the task to the db
    create_task_btn=tk.Button(newtaskwin, command=create_task, width=10, text='Save').grid(row=9, column=0)

When you run the code, this error shows in shell:

Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Program Files\Python311\Lib\tkinter\__init__.py", line 1948, in __call__
return self.func(*args)
^^^^^^^^^^^^^^^^
File "C:\Users\ellio_6\Documents\etasks-main\src\Home.py", line 77, in newtaskwin
TaskNameLbl=tk.Label(tasknameframe, text='Task Name:').grid(row=1, column=0, pady=5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\Python311\Lib\tkinter\__init__.py", line 2549, in grid_configure
self.tk.call(
_tkinter.TclError: cannot use geometry manager grid inside . which already has slaves managed by pack

I know that you can't use more than one grid manager in a parent window, but I'm not doing that here.

I tried to get a list of all the packed and grided widgets; that wasn't much help. I've also tried to run the code by itself in a different file, and that didn't work either.

Using Python 3.

The geometry manager for tasknameframe should be on a new line, so instead of

> tasknameframe=tk.Frame(newtaskwin, relief='groove', highlightbackground='black', highlightthickness=1, width=250).grid()

It should be

tasknameframe=tk.Frame(newtaskwin, relief='groove', 
highlightbackground='black', highlightthickness=1, width=250)
tasknameframe.grid()

Thank you all that posted this in the comments!