diff --git a/ymraster/raster_dtype.py b/ymraster/raster_dtype.py
index a0c98d064dd2396dfc7fec1040bb1b5d3a737470..19e625a6700b6d127eb426cc8a8c8df57e03d4ee 100755
--- a/ymraster/raster_dtype.py
+++ b/ymraster/raster_dtype.py
@@ -168,7 +168,17 @@ class OtbDataType(DataType):
 
 
 class RasterDataType(object):
-    """The usable class to manage raster data types"""
+    """The usable class to manage raster data types
+
+    lstr_dtype can be:
+        - 'uint8'
+        - 'uint16',
+        - 'uint32'
+        - 'int16'
+        - 'int32'
+        - 'float32'
+        - 'float64'
+    """
 
     lstr_dtype = LStrDataType()
     ustr_dtype = UStrDataType()