plt.plot(x, y, marker=r'$uparrow$')
plt.plot(x, y, marker=r'$downarrow$')
import matplotlib.pyplot as plt
#define two arrays for plotting
A = [3, 5, 5, 6, 7, 8]
B = [12, 14, 17, 20, 22, 27]
#create scatterplot, specifying marker size to be 40
plt.scatter(A, B, s=40)
#add arrow to plot
plt.arrow(x=4, y=18, dx=2, dy=5, width=.08)
#display plot
plt.show()