diff --git a/logics/__init__.py b/logics/__init__.py
index fcb859c..768c246 100644
--- a/logics/__init__.py
+++ b/logics/__init__.py
@@ -1,3 +1,4 @@
 from logics.rsltl import Formula_rsLTL
 from logics.bags import BagDescription
+from logics.param_constr import ParamConstraint
 from logics.rsltl_encoder import rsLTL_Encoder