diff --git a/apps/backend/fastapi/app/models/cv.py b/apps/backend/fastapi/app/models/cv.py
index f3305bc..7852df8 100644
--- a/apps/backend/fastapi/app/models/cv.py
+++ b/apps/backend/fastapi/app/models/cv.py
@@ -42,7 +42,7 @@ class CvVersion(Base, IdentifierMixin, TimestampMixin):
     metadata_json: Mapped[dict | None] = mapped_column(JSONB, default=dict)
 
     document: Mapped[CvDocument] = relationship("CvDocument", back_populates="versions")
-    parent: Mapped["CvVersion"] | None = relationship(
+    parent: Mapped["CvVersion | None"] = relationship(
         "CvVersion", remote_side="[CvVersion.id]"
     )
     patches: Mapped[list["CvPatch"]] = relationship("CvPatch", back_populates="version")