fix: handling nested enum correctly in python (#589)

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# Fixes #

Earlier in case of Enums inside nested classes, the enums were treated
as class. This fix makes sure .to_dict() is added only when the object
is no way an enum.

### Checklist
- [x] I acknowledge that all my contributions will be made under the
project's license
- [ ] Run `make test-docker`
- [ ] Verify affected language:
- [ ] Generate [twilio-go](https://github.com/twilio/twilio-go) from our
[OpenAPI specification](https://github.com/twilio/twilio-oai) using the
[build_twilio_go.py](./examples/build_twilio_go.py) using `python
examples/build_twilio_go.py path/to/twilio-oai/spec/yaml
path/to/twilio-go` and inspect the diff
    - [ ] Run `make test` in `twilio-go`
    - [ ] Create a pull request in `twilio-go`
    - [ ] Provide a link below to the pull request
- [ ] I have made a material change to the repo (functionality, testing,
spelling, grammar)
- [ ] I have read the [Contribution
Guidelines](https://github.com/twilio/twilio-oai-generator/blob/main/CONTRIBUTING.md)
and my PR follows them
- [ ] I have titled the PR appropriately
- [ ] I have updated my branch with the main branch
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have added the necessary documentation about the functionality
in the appropriate .md file
- [ ] I have added inline documentation to the code I modified

If you have questions, please create a GitHub Issue in this repository.

Author: tiwarishubham635

src/main/java/com/twilio/oai/CodegenUtils.java

@@ -24,7 +24,9 @@ public static boolean isPropertySchemaEnum(CodegenProperty codegenProperty) {
                 codegenProperty.allowableValues.containsKey(TwilioJavaGenerator.VALUES);
         boolean listEnumValues = codegenProperty.items != null && (codegenProperty.items.allowableValues != null
                 && codegenProperty.items.allowableValues.containsKey(TwilioJavaGenerator.VALUES));
-        return enumValues || listEnumValues;
+        boolean isEnum = enumValues || listEnumValues;
+        codegenProperty.vendorExtensions.put("x-enum-object", isEnum);
+        return isEnum;
     }
 
     public static boolean isParameterSchemaEnum(CodegenParameter codegenParameter) {
@@ -38,7 +40,9 @@ public static boolean isParameterSchemaEnum(CodegenParameter codegenParameter) {
                 codegenParameter.allowableValues.containsKey(TwilioJavaGenerator.VALUES);
         boolean listEnumValues = codegenParameter.items != null && (codegenParameter.items.allowableValues != null
                 && codegenParameter.items.allowableValues.containsKey(TwilioJavaGenerator.VALUES));
-        return enumValues || listEnumValues;
+        boolean isEnum = enumValues || listEnumValues;
+        codegenParameter.vendorExtensions.put("x-enum-object", isEnum);
+        return isEnum;
     }
 
     // TODO: Refactor java code.
@@ -103,4 +107,4 @@ public static boolean isPredefinedEnum(CodegenParameter codegenParameter) {
         }
         return false;
     }
-}
+}

src/main/resources/twilio-python/modelClasses.handlebars

@@ -12,6 +12,6 @@
         def to_dict(self):
             return {
                 {{#vars}}
-                    "{{{vendorExtensions.json-name}}}": {{#if complexType}}{{#containerType}}[{{name}}.to_dict() for {{name}} in self.{{name}}]{{/containerType}}{{^containerType}}self.{{name}}.to_dict(){{/containerType}}{{else}}self.{{name}}{{/if}},{{/vars}}
+                    "{{{vendorExtensions.json-name}}}": {{#if complexType}}{{#containerType}}[{{name}}.to_dict() for {{name}} in self.{{name}}]{{/containerType}}{{^containerType}}self.{{name}}{{^vendorExtensions.x-enum-object}}.to_dict(){{/vendorExtensions.x-enum-object}}{{/containerType}}{{else}}self.{{name}}{{/if}},{{/vars}}
             }
 {{/hasVars}}{{/vendorExtensions.part-of-response-model}}{{/models}}