Many bands in rasterization

[Carlos Leandro Cordeiro]

Hello everyone, I'd like some help. I am rasterizing a shape from the states of Brazil using this command. 

#/usr/bin/env python

# Import python modules

import rsgislib

from rsgislib import vectorutils

inputVector = 'Brasil_bestados_buffer_7km.shp'

inputImage = 'exemplo_albers2_utm_wgs84_buffer_7km.tif'

outputImage = 'raster.tif'

vectorutils.rasterise2Image(inputVector, inputImage, outputImage,shpAtt='SIGLAUF3')

But when I open the image it's like it had more layers than just one. Can anybody help me?

Thank you