Human: Python code to matrix shift columns independently. Assistant: 
Here is a Python code to matrix shift columns independently

import numpy as np

def fshift_columns(mat, shift):
    """
    Shift columns of a matrix by a given amount.
    :param mat: The matrix.
    :param shift: The amount of shift.
    :return: The shifted matrix.
    """
    return np.roll(mat, shift, axis=1)

# Enter the matrix
mat = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])

# Calling the function
print((fshift_columns(mat, 1)))

#Example Output
# [[3 1 2]
#  [6 4 5]
#  [9 7 8]]

#Remember to inspect code for bugs.