Python 2.7: Issues with Dynamic Attribute Access in Custom JSON Encoder
This might be a silly question, but I've been banging my head against this for hours. I'm working on a custom JSON encoder for a web application built with Flask in Python 2.7, and I'm running into issues when trying to dynamically access attributes of an object. My objective is to encode an object that has attributes with names not known until runtime. I'm using the `json` module and have implemented a custom encoder by subclassing `json.JSONEncoder`. However, when I try to access the attributes using `getattr()`, I'm facing a `TypeError` when an attribute is missing. Here’s a simplified version of my encoder: ```python import json class CustomEncoder(json.JSONEncoder): def default(self, obj): if isinstance(obj, MyClass): return { 'name': getattr(obj, 'name', 'N/A'), 'value': getattr(obj, 'value', 'N/A') } return json.JSONEncoder.default(self, obj) ``` When I try to serialize an instance of `MyClass` like this: ```python class MyClass: def __init__(self, name, value): self.name = name self.value = value obj = MyClass('Test', None) json_data = json.dumps(obj, cls=CustomEncoder) print(json_data) ``` I get the output as expected, but if I create an object without the `value` attribute like this: ```python class MyClass: def __init__(self, name): self.name = name obj = MyClass('Test') json_data = json.dumps(obj, cls=CustomEncoder) print(json_data) ``` I encounter a `TypeError: 'NoneType' object is not callable`. It seems that the `getattr()` fallback to 'N/A' is not working correctly when accessing `value` in the absence of the attribute. I’ve tried using `hasattr(obj, 'value')` to check for the attribute before accessing it, but it doesn’t resolve the issue. What could be the reason for this error, and how can I correctly handle such cases without throwing an error during JSON serialization? My development environment is macOS. I'd really appreciate any guidance on this. Any help would be greatly appreciated! This issue appeared after updating to Python stable. Any advice would be much appreciated. Any pointers in the right direction?