diff --git a/src/km3irf/utils.py b/src/km3irf/utils.py
index 2b082925fa829bd60ef1cc839c0472a29144f338..dcfcc8771a5f0bbb32048d06d34795d5832dc411 100644
--- a/src/km3irf/utils.py
+++ b/src/km3irf/utils.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
-from .calc import Calculator
+from calc import Calculator
 from astropy.io import fits
 from os import path
 data_dir = path.join(path.dirname(__file__), 'data')
@@ -27,22 +27,53 @@ def merge_fits(aeff_fits=path.join(data_dir, "aeff.fits"),
     hdu_list = []
     hdu_list.append(fits.PrimaryHDU())
 
-    with fits.open(aeff_fits) as file_aeff:
-        hdu_list.append(file_aeff[1])
+    # with fits.open(aeff_fits) as file_aeff:
+    #     hdu_list.append(file_aeff[1])
+    # hdu_list[1].name = 'EFFECTIVE AREA'
+
+    # with fits.open(psf_fits) as file_psf:
+    #     hdu_list.append(file_psf[1])
+    # hdu_list[2].name = 'POINT SPREAD FUNCTION'
+
+    # with fits.open(edisp_fits) as file_edisp:
+    #     hdu_list.append(file_edisp[1])
+    # hdu_list[3].name = 'ENERGY DISPERSION'
+
+    # with fits.open(bkg_fits) as file_bkg:
+    #     hdu_list.append(file_bkg[1])
+    # hdu_list[4].name = 'BACKGROUND'
+
+    file_aeff = fits.open(aeff_fits) 
+    hdu_list.append(file_aeff[1])
     hdu_list[1].name = 'EFFECTIVE AREA'
 
-    with fits.open(psf_fits) as file_psf:
-        hdu_list.append(file_psf[1])
+    file_psf = fits.open(psf_fits)
+    hdu_list.append(file_psf[1])
     hdu_list[2].name = 'POINT SPREAD FUNCTION'
 
-    with fits.open(edisp_fits) as file_edisp:
-        hdu_list.append(file_edisp[1])
+    file_edisp = fits.open(edisp_fits)
+    hdu_list.append(file_edisp[1])
     hdu_list[3].name = 'ENERGY DISPERSION'
 
-    with fits.open(bkg_fits) as file_bkg:
-        hdu_list.append(file_bkg[1])
+    file_bkg = fits.open(bkg_fits)
+    hdu_list.append(file_bkg[1])
     hdu_list[4].name = 'BACKGROUND'
 
-    new_fits_file = fits.HDUList(hdu)
-    new_fits_file.writeto(f'./data/{output_file}', overwrite=True)
+    
+    new_fits_file = fits.HDUList(hdu_list)
+    # new_fits_file.writeto(f'.data/{output_file}', overwrite=True)
+    # new_fits_file.writeto(output_file, overwrite=True)
+    new_fits_file.writeto(path.join(data_dir, output_file), overwrite=True)
+    # new_fits_file.writeto(f'.data/{output_file}', overwrite=True)
+    # new_fits_file.close()
+
+    # with fits.open(path.join(data_dir, output_file), mode='update') as new_fits_file:
+    #     new_fits_file = fits.HDUList(hdu_list)
+    #     new_fits_file.writeto(path.join(data_dir, output_file), overwrite=True)
+
+    file_aeff.close()
+    file_psf.close()
+    file_edisp.close()
+    file_bkg.close()
 
+# merge_fits()
\ No newline at end of file