from numpy.linalg import norm

The `norm` function from `numpy.linalg` module is used to calculate various matrix and vector norms. It takes an array-like object as input and returns the norm of that object. The norm can be specified using the optional `ord` parameter, which can take values like 1, 2, -1, -2, etc.

For example, to calculate the Euclidean norm of a vector `v`, we can use the following code:

import numpy as np

v = np.array([1, 2, 3])
norm_v = np.linalg.norm(v)
print(norm_v)

This will output `3.74165738677`, which is the Euclidean norm of the vector `[1, 2, 3]`.