diff --git a/generate_bootstrap_json.py b/generate_bootstrap_json.py
index e804603..aafc4af 100755
--- a/generate_bootstrap_json.py
+++ b/generate_bootstrap_json.py
@@ -6,7 +6,6 @@
 import json
 import os
 import sys
-from typing import Dict
 
 import spack.deptypes as dt
 import spack.spec
@@ -17,6 +16,7 @@
 # "spec": root spec to be matched
 # "binaries": list of tuples (pkg name, dag hash, sha256 sum)
 
+
 def sha256(path):
     fn = hashlib.sha256()
     with open(path, "rb") as f: