3. Construct two new variable: monthly returns of TSX and BTC.

Hint: Monthly percentage returns are defined as the price appreciation with respect to the last months prices: Rt = (Pt - Pt1) / Pt1.

You can calculate the returns following the equation or use the percentage change function of Pandas: .pct_change().

Alternatively, you can work with the log return of each month is calculated with respect to the previous months values using the log of prices,

i.e. Rt = ln(Pt) - ln(Pt1)