Visual Studio 2019 python 3.7 64-bit, unresolved import warning

Question

I have installed matplotlib and numpy through visual studio, python environments. The following code works fine (plots a sine wave), but the first two lines (imports) are flagged as error/warning in Visual Studio's editor (with that jagged red underline). Is there a reason for that?

I am VERY new to python, so please tell me if I have to provide further information.

import matplotlib.pyplot as plt
import numpy as np

x=np.arange(0,2*np.pi,0.01)
y=np.sin(x)
plt.plot(x,y)
plt.show()

Answer 1

closing and reopening the project did not help, but closing and reopening Visual Studio (after package installation) solved the problem for me.