Matplotlib 플롯에서 Y축 제한을 사용자 정의하는 방법은 무엇입니까?

ax = plt.gca()

ax.set_ylim([ymin, ymax])

import matplotlib.pyplot as plt

plt.figure(1, figsize = (8.5,11))
plt.suptitle('plot title')
ax = []
aPlot = plt.subplot(321, axisbg = 'w', title = "Year 1")
ax.append(aPlot)
plt.plot(paramValues,plotDataPrice[0], color = '#340B8C',
     marker = 'o', ms = 5, mfc = '#EB1717')
plt.xticks(paramValues)
plt.ylabel('Average Price')
plt.xlabel('Mark-up')
plt.grid(True)

# Set y-axis limits
ax = plt.gca()
ax.set_ylim([20, 250])