我得到的错误是：
ValueError：参数的类型不受支持
代码：

async def add(ctx, el: str, email: str, password: str):
    con= sqlite3.connect("db.sqlite")
    c = con.cursor()
    c.execute("SELECT type FROM accounts WHERE type=?", (el,))
    results = c.fetchall()
    if len(results) == 0:
        await ctx.send("there is no type with this")
    else:
        c.execute("UPDATE accounts SET type = ?, email = ?, password = ? ;", {el, email, password})
        print("done")
        await ctx.send("done")
    con.commit()
    con.close()

错误跟踪：

Ignoring exception in command add:
Traceback (most recent call last):
  File "C:\Users\user\AppData\Local\Programs\Python\Python310\lib\site-packages\discord\commands\core.py", line 127, in wrapped
    ret = await coro(arg)
  File "C:\Users\user\AppData\Local\Programs\Python\Python310\lib\site-packages\discord\commands\core.py", line 911, in _invoke
    await self.callback(ctx, **kwargs)
  File "C:\Users\user\Desktop\Sidtho\main.py", line 42, in add
    c.execute("UPDATE accounts SET type = ?, email = ?, password = ? ;", {el, email, password})
ValueError: parameters are of unsupported type

上述异常是以下异常的直接原因：

Traceback (most recent call last):
  File "C:\Users\user\AppData\Local\Programs\Python\Python310\lib\site-packages\discord\bot.py", line 1008, in invoke_application_command
    await ctx.command.invoke(ctx)
  File "C:\Users\user\AppData\Local\Programs\Python\Python310\lib\site-packages\discord\commands\core.py", line 359, in invoke
    await injected(ctx)
  File "C:\Users\user\AppData\Local\Programs\Python\Python310\lib\site-packages\discord\commands\core.py", line 135, in wrapped
    raise ApplicationCommandInvokeError(exc) from exc
discord.errors.ApplicationCommandInvokeError: Application Command raised an exception: ValueError: parameters are of unsupported type