diff --git a/snap/local/build.sh b/snap/local/build.sh
index bbe5ba323..eccb99760 100755
--- a/snap/local/build.sh
+++ b/snap/local/build.sh
@@ -39,4 +39,4 @@ docker run \
   -w "/certbot" \
   -e "PIP_EXTRA_INDEX_URL=http://localhost:8080" \
   "adferrand/snapcraft:${DOCKER_ARCH}-stable" \
-  snapcraft
+  bash -c "snapcraft clean && snapcraft"
diff --git a/tools/simple_http_server.py b/tools/simple_http_server.py
index 24c55962d..32f35ec69 100755
--- a/tools/simple_http_server.py
+++ b/tools/simple_http_server.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 """A version of Python's SimpleHTTPServer that flushes its output."""
 import sys
 
@@ -8,6 +8,7 @@ except ImportError:
     from BaseHTTPServer import HTTPServer
     from SimpleHTTPServer import SimpleHTTPRequestHandler
 
+
 def serve_forever(port=0):
     """Spins up an HTTP server on all interfaces and the given port.