Parameter=period2 has an invalid type

Steps to reproduce the behavior:

Whit this code

```
ticker_yf = yf.Ticker('MMM', asynchronous=False)
balance_sheet = ticker_yf.balance_sheet(frequency="a")
```

I got this error: 'MMM': 'Parameter=period2 has an invalid type' from balance_sheet().

The same for cash_flow() and income_statement() methods.

I am using yahooquery version 2.4.0 on Windows 11 and with Python 3.13.3

