A start

data = {
    'person1': {
        'first': 'Geoff',
        'last': 'Skerlan',
        'address': {
            'street': "my street",
            'number_unit': 666,
        }
    },
    'person2': {
        'first': 'Dan',
        'last': 'Huckson',
        'address': {
            'street': "His street",
            'number_unit': 777,
        }
    }
}

class cache:
    def __init__(self):
        self.nodes = {}

    def get(self, node):
        if node in self.nodes:
            return self.nodes.get(node)
        return None

    def set(self, node, value):
        self.nodes[node] = value


c = cache()

c.set('abc', 123)
print('value = ', c.get('abc'))