Sarah is considering investing in stocks and plans to buy and hold a certain number of shares. She anticipates an annual return of $10\%$ from the stocks. However, she incurs brokerage fees for both buying and selling the stocks. The brokerage fee for buying is $1\mathrm{.}5\%$ of the investment amount, and the fee for selling is also $1\mathrm{.}5\%$ of the final selling amount. Sarah plans to hold the stocks for one year before selling.

a$)$ Calculate the Expected Rate of Return $($ERR$)$ for Sarah's investment after considering brokerage fees.

b$)$ If Sarah invests $$20,000$ in stocks, calculate the net gain after one year, accounting for both the return from the stocks and the brokerage fees.