diff --git a/conftest.py b/conftest.py
index 58f4c248a..6e1835d31 100644
--- a/conftest.py
+++ b/conftest.py
@@ -409,8 +409,6 @@ def run_web_server(q, log_filepath, build_dir):
     sys.stdout = log_fh
     sys.stderr = log_fh
 
-    test_prefix = "/src/tests/"
-
     class Handler(http.server.SimpleHTTPRequestHandler):
         def log_message(self, format_, *args):
             print(
diff --git a/lgtm.yml b/lgtm.yml
new file mode 100644
index 000000000..2649a0e5a
--- /dev/null
+++ b/lgtm.yml
@@ -0,0 +1,8 @@
+queries:
+  - exclude: py/import-and-import-from
+
+extraction:
+  cpp:
+    prepare:
+      packages:
+        - python3-yaml
diff --git a/pyodide_build/mkpkg.py b/pyodide_build/mkpkg.py
index b273dc86e..0a127f954 100755
--- a/pyodide_build/mkpkg.py
+++ b/pyodide_build/mkpkg.py
@@ -36,9 +36,10 @@ def _extract_sdist(pypi_metadata: Dict[str, Any]) -> Dict:
     )
 
 
-def _get_metadata(package: str) -> Tuple[Dict, Dict]:
+def _get_metadata(package: str, version: Optional[str] = None) -> Tuple[Dict, Dict]:
     """Download metadata for a package from PyPi"""
-    url = f"https://pypi.org/pypi/{package}/json"
+    version = ("/" + version) if version is not None else ""
+    url = f"https://pypi.org/pypi/{package}{version}/json"
 
     with urllib.request.urlopen(url) as fd:
         pypi_metadata = json.load(fd)
@@ -55,13 +56,7 @@ def make_package(package: str, version: Optional[str] = None):
     """
     import yaml
 
-    version = ("/" + version) if version is not None else ""
-    url = f"https://pypi.org/pypi/{package}{version}/json"
-
-    with urllib.request.urlopen(url) as fd:
-        json_content = json.load(fd)
-
-    sdist_metadata, pypi_metadata = _get_metadata(package)
+    sdist_metadata, pypi_metadata = _get_metadata(package, version)
     url = sdist_metadata["url"]
     sha256 = sdist_metadata["digests"]["sha256"]
     version = pypi_metadata["info"]["version"]
@@ -141,8 +136,9 @@ complex things.""".strip()
 def main(args):
     package = args.package[0]
     if args.update:
-        return update_package(package)
-    return make_package(package, args.version)
+        update_package(package)
+        return
+    make_package(package, args.version)
 
 
 if __name__ == "__main__":
diff --git a/pyodide_build/pywasmcross.py b/pyodide_build/pywasmcross.py
index 2751f33fc..ac1cc1f7b 100755
--- a/pyodide_build/pywasmcross.py
+++ b/pyodide_build/pywasmcross.py
@@ -273,8 +273,6 @@ def handle_command(line, args, dryrun=False):
             optflag = arg
             break
 
-    lapack_dir = None
-
     used_libs = set()
 
     # Go through and adjust arguments
diff --git a/src/pyodide-py/pyodide/webloop.py b/src/pyodide-py/pyodide/webloop.py
index 822c4d36d..74b3a44c3 100644
--- a/src/pyodide-py/pyodide/webloop.py
+++ b/src/pyodide-py/pyodide/webloop.py
@@ -1,5 +1,4 @@
 import asyncio
-from asyncio import tasks, futures
 import time
 import contextvars
 
@@ -136,7 +135,7 @@ class WebLoop(asyncio.AbstractEventLoop):
 
         if delay < 0:
             raise ValueError("Can't schedule in the past")
-        h = asyncio.Handle(callback, args, self, context=context)
+        h = asyncio.Handle(callback, args, self, context=context)  # type: ignore
         setTimeout(create_once_callable(h._run), delay * 1000)
         return h
 
@@ -177,7 +176,7 @@ class WebLoop(asyncio.AbstractEventLoop):
 
         Copied from ``BaseEventLoop.create_future``
         """
-        return futures.Future(loop=self)
+        return asyncio.futures.Future(loop=self)
 
     def create_task(self, coro, *, name=None):
         """Schedule a coroutine object.
@@ -188,7 +187,7 @@ class WebLoop(asyncio.AbstractEventLoop):
         """
         self._check_closed()
         if self._task_factory is None:
-            task = tasks.Task(coro, loop=self, name=name)
+            task = asyncio.tasks.Task(coro, loop=self, name=name)
             if task._source_traceback:
                 # Added comment:
                 # this only happens if get_debug() returns True.
@@ -196,7 +195,7 @@ class WebLoop(asyncio.AbstractEventLoop):
                 del task._source_traceback[-1]
         else:
             task = self._task_factory(self, coro)
-            tasks._set_task_name(task, name)
+            asyncio.tasks._set_task_name(task, name)
 
         return task
 
diff --git a/src/pyodide.js b/src/pyodide.js
index c25e2ae9d..d5f626d67 100644
--- a/src/pyodide.js
+++ b/src/pyodide.js
@@ -54,7 +54,7 @@ globalThis.languagePluginLoader = (async () => {
   } else if (self.importScripts) { // webworker
     loadScript = async (url) => {  // This is async only for consistency
       self.importScripts(url);
-    }
+    };
   } else {
     throw new Error("Cannot determine runtime environment");
   }
@@ -97,7 +97,7 @@ globalThis.languagePluginLoader = (async () => {
       }
     }
     if (sharedLibsOnly) {
-      onlySharedLibs = new Map();
+      let onlySharedLibs = new Map();
       for (let c of toLoad) {
         if (c[0] in sharedLibraries) {
           onlySharedLibs.set(c[0], toLoad.get(c[0]));
@@ -129,7 +129,8 @@ globalThis.languagePluginLoader = (async () => {
     if (toLoad.size === 0) {
       return Promise.resolve('No new packages to load');
     } else {
-      messageCallback(`Loading ${[...toLoad.keys()].join(', ')}`)
+      let packageNames = Array.from(toLoad.keys()).join(', ');
+      messageCallback(`Loading ${packageNames}`);
     }
 
     // If running in main browser thread, try to catch errors thrown when
@@ -170,9 +171,11 @@ globalThis.languagePluginLoader = (async () => {
           messageCallback(`${pkg} already loaded from ${loaded}`);
           continue;
         } else {
-          errorCallback(`URI mismatch, attempting to load package ${pkg} from ${
-              uri} while it is already loaded from ${
-              loaded}. To override a dependency, load the custom package first.`);
+          errorCallback(
+              `URI mismatch, attempting to load package ${pkg} from ${uri} ` +
+              `while it is already loaded from ${
+                  loaded}. To override a dependency, ` +
+              `load the custom package first.`);
           continue;
         }
       }
@@ -225,8 +228,8 @@ globalThis.languagePluginLoader = (async () => {
 
     let resolveMsg;
     if (packageList.length > 0) {
-      let package_names = packageList.join(', ');
-      resolveMsg = `Loaded ${packageList}`;
+      let packageNames = packageList.join(', ');
+      resolveMsg = `Loaded ${packageNames}`;
     } else {
       resolveMsg = 'No packages loaded';
     }
@@ -268,18 +271,17 @@ globalThis.languagePluginLoader = (async () => {
    * messages (optional)
    * @returns {Promise} Resolves to ``undefined`` when loading is complete
    */
-  Module.loadPackage =
-      async function(names, messageCallback, errorCallback) {
+  Module.loadPackage = async function(names, messageCallback, errorCallback) {
     if (!Array.isArray(names)) {
       names = [ names ];
     }
     // get shared library packages and load those first
     // otherwise bad things happen with linking them in firefox.
-    sharedLibraryNames = [];
+    let sharedLibraryNames = [];
     try {
-      sharedLibraryPackagesToLoad =
+      let sharedLibraryPackagesToLoad =
           recursiveDependencies(names, messageCallback, errorCallback, true);
-      for (pkg of sharedLibraryPackagesToLoad) {
+      for (let pkg of sharedLibraryPackagesToLoad) {
         sharedLibraryNames.push(pkg[0]);
       }
     } catch (e) {
@@ -332,7 +334,7 @@ globalThis.languagePluginLoader = (async () => {
                            errorCallback || console.error));
     loadPackageChain = loadPackageChain.then(() => promise.catch(() => {}));
     await promise;
-  }
+  };
 
   ////////////////////////////////////////////////////////////
   // Fix Python recursion limit
@@ -425,7 +427,7 @@ globalThis.languagePluginLoader = (async () => {
           continue;
         }
         if (typeof (value) === "function") {
-          Module.public_api[key] = function() { throw Error(fatal_error_msg); }
+          Module.public_api[key] = function() { throw Error(fatal_error_msg); };
         }
       }
     } catch (_) {
@@ -658,12 +660,11 @@ globalThis.languagePluginLoader = (async () => {
     let QUOTE = 3;
     let QUOTE_ESCAPE = 4;
     let paren_depth = 0;
-    let arg_start = 0;
     let arg_is_obj_dest = false;
     let quote_start = undefined;
     let state = START_ARG;
     // clang-format off
-    for (i = idx; i < funcstr.length; i++) {
+    for (let i = idx; i < funcstr.length; i++) {
       let x = funcstr[i];
       if(state === QUOTE){
         switch(x){