It is standard matplotlib.pyplot:
...
import matplotlib.pyplot as plt
plt.ylim(10, 40)
Or simpler, as mwaskom comments below:
ax.set(ylim=(10, 40))

It is standard matplotlib.pyplot:
...
import matplotlib.pyplot as plt
plt.ylim(10, 40)
Or simpler, as mwaskom comments below:
ax.set(ylim=(10, 40))
