Fix circular imports caused by type annotations

1 files changed, 6 insertions, 1 deletions

diff --git a/polymatrix/expression/mixins/additionexprmixin.py b/polymatrix/expression/mixins/additionexprmixin.py
index 200c328..02b45a4 100644
--- a/polymatrix/expression/mixins/additionexprmixin.py
+++ b/polymatrix/expression/mixins/additionexprmixin.py
@@ -1,10 +1,15 @@
+from __future__ import annotations
+
 import abc
 import math
+import typing
+
+if typing.TYPE_CHECKING:
+    from polymatrix.expressionstate.abc import ExpressionState
 
 from polymatrix.utils.getstacklines import FrameSummary
 from polymatrix.polymatrix.init import init_poly_matrix
 from polymatrix.polymatrix.abc import PolyMatrix
-from polymatrix.expressionstate.abc import ExpressionState
 from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
 from polymatrix.expression.utils.broadcastpolymatrix import broadcast_poly_matrix