Feedback about importing ploting

#1

Ladies and gentlemen. I am a novice and with a basic understanding of python. So I am not trying to show off at all. in this tutorial under the title essentials of python under the title Why Write functions. I came across this example
def generate_data(n):
ϵ_values = []
for I in range(n):
e = np.random.randn()
ϵ_values.append(e)
return ϵ_values

data = generate_data(100)
plt.plot(data)
plt.show()

without importing the following
import numpy as np
from matplotlib import pyplot as plot
and yet it has plotted the graph. I ma using python 3 Spyder. How that happened. How is that possible?
Thank you