diff --git a/.gitignore b/.gitignore
index 95439a9..d4b47f4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 .venv
 
-__pycache__
\ No newline at end of file
+__pycache__
diff --git a/cryptarchia/cryptarchia.py b/cryptarchia/cryptarchia.py
index dc73d9f..da16c7d 100644
--- a/cryptarchia/cryptarchia.py
+++ b/cryptarchia/cryptarchia.py
@@ -143,7 +143,7 @@ class LedgerState:
     A snapshot of the ledger state up to some height
     """
 
-    height: int = None
+    block: Id = None
     nonce: bytes = None
     total_stake: int = None
 
@@ -216,8 +216,7 @@ class Leader:
         return r < MOCK_LEADER_VRF.ORDER * phi(f, relative_stake)
 
     def propose_block(self, slot: Slot, parent: BlockHeader) -> BlockHeader:
-        assert self.is_leader_at(slot)
-        return BlockHeader(parent=parent.id(), slot=slot, _id=Id(b"TODO"))
+        return BlockHeader(parent=parent.id(), slot=slot)
 
 
 if __name__ == "__main__":