Discord.py RuntimeWarning: coroutine 'Command.__call__' was never awaited

I'm creating a bot that controls a command panel, but am currently running into some issues I don't know how to fix. I've also looked at some questions with similar titles, but it seems like they are running into a different issue.

from pyautogui import *
import pyautogui
import win32gui
import time
import clipboard
import discord
from discord.ext import commands

botToken = "No"
client = commands.Bot(command_prefix='!', help_command=None)

fileLocation = "C:/Users/Admin/Downloads/Program.exe"

def screenshot():
    with open("hwnd.txt", "r") as file:
        hwnd = int(file.read())
    win32gui.SetForegroundWindow(hwnd)
    x, y, x1, y1 = win32gui.GetClientRect(hwnd)
    x, y = win32gui.ClientToScreen(hwnd, (x, y))
    x1, y1 = win32gui.ClientToScreen(hwnd, (x1 - x, y1 - y))
    pyautogui.screenshot("screenshot.png",region=(x, y-27, x1, y1+27))

@client.command()
async def start(ctx):
    if clipboard.paste != fileLocation:
        clipboard.copy(fileLocation)
    pyautogui.hotkey('winleft', 'r')
    time.sleep(0.5)
    pyautogui.hotkey('ctrl', 'v')
    pyautogui.press("enter")
    time.sleep(0.5)
    with open("hwnd.txt","w") as file:
        hwnd = win32gui.FindWindow(None, fileLocation.replace("/","\\"))
        file.write(str(hwnd))
    time.sleep(0.1)
    screenshot()
    time.sleep(0.1)
    await ctx.channel.send("Screenshot:", file=discord.File("screenshot.png"))

client.run(botToken)

Error message:

RuntimeWarning: coroutine 'Command.__call__' was never awaited
  screenshot()
RuntimeWarning: Enable tracemalloc to get the object allocation traceback

Edit: The issue was a screenshot command I didn't include in the snippet.