diff --git a/interface/TextMiningService.py b/interface/TextMiningService.py
index 48f38bec8670d06ca1c335b829298471d8cf7518..f2b07c61d13ca95213e44de176bfc5f50cbe5a2b 100644
--- a/interface/TextMiningService.py
+++ b/interface/TextMiningService.py
@@ -25,7 +25,7 @@ class TextMiningService(metaclass=ABCMeta):
         pass
 
     @abstractmethod
-    def get_co_occurrences(self, entity: str) -> List[str]:
+    def get_co_occurrences(self, entity: str) -> List[CoOccurrence]:
         """
         Co-occurrences at publication level.