from numpy import random as ran
t = range(50)
-x = (ran.rand(50)*50) + 2000 # I don't have real data
-plt.plot(t, x)
+y = (ran.rand(50)*50) + 2000 # I don't have real data
+plt.plot(t, y)
plt.title('Some time series with left title', loc='left')
plt.ylabel('Mass of test mass over time')
plt.show()