Decodes column source data encoded as lists or base64 strings.

def from_json(self, json, models=None):
        ''' Decodes column source data encoded as lists or base64 strings.
        '''
        if json is None:
            return None
        elif not isinstance(json, dict):
            raise DeserializationError("%s expected a dict or None, got %s" % (self, json))
        new_data = {}
        for key, value in json.items():
            key = self.keys_type.from_json(key, models)
            if isinstance(value, dict) and '__ndarray__' in value:
                new_data[key] = decode_base64_dict(value)
            elif isinstance(value, list) and any(isinstance(el, dict) and '__ndarray__' in el for el in value):
                new_list = []
                for el in value:
                    if isinstance(el, dict) and '__ndarray__' in el:
                        el = decode_base64_dict(el)
                    elif isinstance(el, list):
                        el = self.values_type.from_json(el)
                    new_list.append(el)
                new_data[key] = new_list
            else:
                new_data[key] = self.values_type.from_json(value, models)
        return new_data