def load(self):
        if os.path.exists(self.path):
            with open(self.path, 'r') as f:
                self.body_labels = collections.OrderedDict(json.load(f))
def pop(self, key, default=None):
        value = self._collection.pop(key, default)
        if isinstance(value, Proxy):
            value = value.get()
        return value