Remove unused imports

jupyterlite_xeus_python/build.py

@@ -267,7 +267,7 @@ def build_and_pack_emscripten_env(
 
     # Bail early if there is nothing to do
     if bail_early and not force:
-        return []
+        return ""
 
     orig_config = os.environ.get("CONDARC")
 

jupyterlite_xeus_python/env_build_addon.py

@@ -2,19 +2,10 @@
 import json
 import os
 from pathlib import Path
-import requests
-import shutil
-from subprocess import check_call, run, DEVNULL
 from tempfile import TemporaryDirectory
-from urllib.parse import urlparse
-
-import yaml
 
 from traitlets import List, Unicode
 
-from empack.pack import pack_env, DEFAULT_CONFIG_PATH
-from empack.file_patterns import PkgFileFilter, pkg_file_filter_from_yaml
-
 from jupyterlite_core.constants import (
     SHARE_LABEXTENSIONS,
     LAB_EXTENSIONS,
@@ -42,7 +33,7 @@ class XeusPythonEnv(FederatedExtensionAddon):
     )
 
     empack_config = Unicode(
-        None,
+        "",
         config=True,
         allow_none=True,
         description="The path or URL to the empack config file",