hstack import no longer needed
@@ -4,7 +4,7 @@ import copy
from os.path import split
import numpy as np
import astropy.units as u
-from astropy.table import Table, hstack
+from astropy.table import Table
import yaml
from gammapy.modeling import Covariance, Parameter, Parameters
from gammapy.utils.scripts import make_name, make_path
