def edge_threshold(grad_mag, thresh):

    """
    Takes the array of gradient magnitude values and suppresses pixels below the threshold value.

    grad_mag: Gradient magnitude for an image which is an array of the same shape as the original image.
    thresh: Threshold value for which pixels to include in edge detection.

    return: Array of of gradient magnitude values where pixel values below threshold are suppressed.
    """

    grad_mag_thresh = grad_mag.copy()
    grad_mag_thresh[grad_mag_thresh < thresh] = 0


    return grad_mag_thresh