diff --git a/specs/deneb/p2p-interface.md b/specs/deneb/p2p-interface.md
index f8124c92d..eedc2e661 100644
--- a/specs/deneb/p2p-interface.md
+++ b/specs/deneb/p2p-interface.md
@@ -97,11 +97,12 @@ class BlobIdentifier(Container):
 
 ```python
 def verify_blob_sidecar_inclusion_proof(blob_sidecar: BlobSidecar) -> bool:
+    gindex = get_subtree_index(get_generalized_index(BeaconBlockBody, 'blob_kzg_commitments', blob_sidecar.index))
     return is_valid_merkle_branch(
         leaf=blob_sidecar.kzg_commitment.hash_tree_root(),
         branch=blob_sidecar.kzg_commitment_inclusion_proof,
         depth=KZG_COMMITMENT_INCLUSION_PROOF_DEPTH,
-        index=get_subtree_index(get_generalized_index(BeaconBlockBody, 'blob_kzg_commitments', blob_sidecar.index)),
+        index=gindex,
         root=blob_sidecar.signed_block_header.message.body_root,
     )
 ```