Every time I change the `figsize` the size does not change

Question

Here is the code below.

plt.figure(figsize=[15,7])
sm.tsa.seasonal_decompose(bitcoin_month.Weighted_Price).plot()
print("Dickey–Fuller test: p=%f" % sm.tsa.stattools.adfuller(bitcoin_month.Weighted_Price)[1])
plt.show()

When I release it I get the following output.

Every time I change the figsize the size does not change.

Please assist.