diff --git a/python/obitools3/obidms/obidmscolumn/capidmscolumn.pyx b/python/obitools3/obidms/obidmscolumn/capidmscolumn.pyx
index 4ca2cbb..3981580 100644
--- a/python/obitools3/obidms/obidmscolumn/capidmscolumn.pyx
+++ b/python/obitools3/obidms/obidmscolumn/capidmscolumn.pyx
@@ -65,6 +65,9 @@ cdef class OBIDMS_column:
              
     def get_data_type(self):
         return self.data_type
+    
+    def get_nb_lines_used(self):
+        return obi_column_get_nb_lines_used(self.pointer)
         
     @staticmethod
     def open(dms_name, column_name,