diff --git a/cml/ports/source_adapters.py b/cml/ports/source_adapters.py
index a183a875ba737a29a846a110ef1f9a0fbe7fa279..2415b694e2c1da6dfc9b339b57260e153664a073 100644
--- a/cml/ports/source_adapters.py
+++ b/cml/ports/source_adapters.py
@@ -42,6 +42,7 @@ class PandasBlock:
 
     def __init__(self, data_block, relatives=None):
         self.__data_block = data_block
+        self.relatives = relatives
 
     def __str__(self):
         return str(self.__data_block)