Error in Jupyter notebook even after importing the required library

Question

I'm getting an NameError in jupyter notebook even after importing numpy as np. Any idea how to go about it will be appreciated

%matplotlib inline
%config InlineBackend.figure_format = 'retina'

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 1, 300)
for i in range(2, 6, 2):
    plt.plot(x, np.sin(np.pi*x)*np.sin(2*i*np.pi*x))

Error

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Input In [1], in <cell line: 1>()
----> 1 x = np.linspace(0, 1, 300)
      2 for i in range(2, 6, 2):
      3     plt.plot(x, np.sin(np.pi*x)*np.sin(2*i*np.pi*x))

NameError: name 'np' is not defined