Issue with nibabel.read_img_data

issue_read_img_data.py

from os  import path 
import numpy as np
import matplotlib.pyplot as plt
from nibabel import load
from nibabel.loadsave import  read_img_data


# Local import to $NIPY/examples/labs/need_data
from get_data_light import DATA_DIR, get_first_level_dataset

#######################################
# Data and analysis parameters
#######################################

# volume mask
# This dataset is large
get_first_level_dataset()
img_path = path.join(DATA_DIR, 's12069_swaloc1_corr.nii.gz')
img = load(img_path)
im1 = img.get_data()[:, :, :, 0]
im2 = read_img_data(img)[:, :, :, 0]
# affine = img.get_affine()

plt.figure()
plt.subplot(121)
plt.imshow(im1[:, :, 20])
plt.subplot(122)
plt.imshow(im2[:, :, 20])
plt.show()