diff --git a/python/obitools3/obidms/_obidmscolumn_seq.pxd b/python/obitools3/obidms/_obidmscolumn_seq.pxd
index 8658f8f..136a9a2 100644
--- a/python/obitools3/obidms/_obidmscolumn_seq.pxd
+++ b/python/obitools3/obidms/_obidmscolumn_seq.pxd
@@ -7,6 +7,10 @@ from ._obidms       cimport OBIView, OBIDMS_column, OBIDMS_column_multi_elts
 cdef class OBIDMS_column_seq(OBIDMS_column):
     cpdef object get_line(self, index_t line_nb)
     cpdef set_line(self, index_t line_nb, object value)
+    
+    # TO DISCUSS : 
+    # I'am not sure that this method has to be declared here
+    # Alignment must be declared outside of the sequence object
     cpdef align(self, 
                 OBIView score_view,
                 OBIDMS_column score_column,