gistfile1.py

%matplotlib qt

import numpy as np
import matplotlib.pyplot as plt
plt.style.use('bmh')

plt.figure(figsize = (12, 6))

for i in range(10):
    x = np.arange(i * 10, i * 10 + 10)
    y_var1 = np.random.randint(1, 5, 10)
    y_var2 = np.random.randint(5, 8, 10)
    line1, = plt.plot(x, y_var1, color = 'k')
    line2, = plt.plot(x, y_var2, color = 'g')
    if i==0:
        line1.set_label("variable1")
        line2.set_label("variable2")
    plt.legend()
    plt.ylim(0, 9)