[Python] Getting ROI as 2d numpy array using pyqtgraph.ROI.getArrayRegion

I am trying to do image processing using pyqtgraph.ROI. I am able to draw multiple ROI on the image and manipulate them but I am unable to merge the ROIs and extract the information as an numpy array. It seems like I am missing some basic things but I couldn´t find a solution addressing the issue. (I am a new user and sorry if it is a silly question. Thanks in advance!)

My code:

## Define ROIs
plt2 = pg.image(image)

roi_circle1 = pg.CircleROI([pos_x, pos_y], [2*radius_of_circle, 2*radius_of_circle], pen=pg.mkPen('r',width=2))

plt2.addItem(roi_circle1)

roi0 = pg.MultiRectROI([[pos_x+radius_of_circle, 0], [pos_x+radius_of_circle, pos_y]], width=5, pen=(2,9)

plt2.addItem(roi0)

plt2.setFixedSize(1000, 1000)
plt2.show()

## Now I am trying to use one of the ROI object to crop the area as an numpy output:
testmat=np.random.random((np.shape(image)))
test_roi_image=pg.ROI.getArrayRegion(testmat,roi0,axes=(0, 1), returnMappedCoords=False)

## I am getting an error:
test_roi_image=pg.ROI.getArrayRegion(testmat,roi0,axes=(0, 1),returnMappedCoords=False)


TypeError: getArrayRegion() missing 1 required positional argument: 'img'

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