Create a shadow block for None if an argument of a python function has a default value of None.

Author: lizlooney

src/blocks/utils/value.ts

@@ -50,9 +50,7 @@ export function valueForFunctionArgInput(argType: string, argDefaultValue: strin
       break;
     case 'str':
       if (argDefaultValue === 'None') {
-        // TODO(lizlooney): Make a block for python None
-        // In RobotPy function hal.report(), the arg named feature has a default value of None.
-        return null;
+        return createNoneShadowValue()
       }
       // If argDefaultValue is surrounded by single or double quotes, it's a literal string.
       if (argDefaultValue.startsWith("'") && argDefaultValue.endsWith("'") ||
@@ -105,3 +103,11 @@ export function createBooleanShadowValue(boolValue: boolean): any {
     },
   }
 }
+
+export function createNoneShadowValue(): any {
+  return {
+    'shadow': {
+      'type': 'mrc_none',
+    },
+  }
+}