Wrap your dict with AccessRecorder to see what keys / values have actually been used.

dict_access_recorder.py

class AccessRecorder:
    def __init__(self, original_dict):
        self.original_dict = original_dict
        self.accessed_keys = set()
        self.accessed_values = {}
        self._is_list = isinstance(original_dict, list)

    def _log_key_value(self, key, value):
        self.accessed_keys.add(key)
        self.accessed_values[key] = value

    def __getitem__(self, key):
        value = self.original_dict[key]
        if isinstance(value, dict):
            value = AccessRecorder(value)
        elif isinstance(value, list):
            value = [AccessRecorder(item) for item in value]
        self._log_key_value(key, value)
        return value

    def get(self, key, default=None):
        if key in self.original_dict:
            return self.__getitem__(key)
        else:
            return default

    def create_snapshot(self):
        snapshot = {}
        for key in self.accessed_keys:
            value = self.accessed_values[key]
            if isinstance(value, AccessRecorder):
                snapshot[key] = value.create_snapshot()
            elif isinstance(value, list):
                snapshot[key] = [item.create_snapshot() for item in value]
            else:
                snapshot[key] = value
        if self._is_list:
            snapshot = [item for item in snapshot.values()]
        return snapshot

# Example usage:
my_dict = {'a': [{'x': 'y', 'nbo': 'sjfk'}, {'sds': 'pff'}], 'b': 2, 'c': 3}
access_recorder = AccessRecorder(my_dict)

# Accessing keys and values
print(access_recorder['a'][0]['x'])
print(access_recorder['c'])

# Creating a snapshot
snapshot = access_recorder.create_snapshot()
print("Snapshot:", snapshot) # Snapshot: {'c': 3, 'a': [{'x': 'y'}, {}]}