diff --git a/wavelength_calibration.py b/wavelength_calibration.py
index 11a19bb..a8d2d22 100644
--- a/wavelength_calibration.py
+++ b/wavelength_calibration.py
@@ -92,5 +92,5 @@ def only_keep_calib( peaks_data , peaks_calib ):
 
     return np.array(
         [ peaks_data[ i ] for i in peaks[ 1 : ] ], # remove the first -1 value
-        dtyp = int,
+        dtype = int,
     )