@ -152,10 +152,6 @@ class relation (object):
if isinstance(attributes[0], list):
attributes = attributes[0]
# Avoiding duplicated attributes
if len(set(attributes)) != len (attributes):
raise Exception('Duplicated attributes in projection')
ids = self.header.getAttributesId(attributes)
if len(ids) == 0 or len(ids) != len(attributes):