Add a proxy to get global objects from Python

src/pyodide.js

@@ -235,6 +235,7 @@ var languagePluginLoader = new Promise((resolve, reject) => {
   let PUBLIC_API = [
     'loadPackage',
     'loadedPackages',
+    'py',
     'pyimport',
     'repr',
     'runPython',
@@ -277,6 +278,8 @@ var languagePluginLoader = new Promise((resolve, reject) => {
           .then((response) => response.json())
           .then((json) => {
             fixRecursionLimit(window.pyodide);
+            window.pyodide.py =
+                window.pyodide.runPython('import sys\nsys.modules["__main__"]');
             window.pyodide = makePublicAPI(window.pyodide, PUBLIC_API);
             window.pyodide._module.packages = json;
             resolve();

test/test_python.py

@@ -599,3 +599,14 @@ def test_runpythonasync_exception_after_import(selenium_standalone):
         assert "ZeroDivisionError" in str(e)
     else:
         assert False
+
+
+def test_py(selenium_standalone):
+    selenium_standalone.run(
+        """
+        def func():
+            return 42
+        """
+    )
+
+    assert selenium_standalone.run_js('return pyodide.py.func()') == 42