Load expectation config based on operator parameters. If provided expectations_json is a file the config will
        be loaded from this file. Otherwise we'll try to load the config as a string.
        :return:

def _load_json(self):
        """
        Load expectation config based on operator parameters. If provided expectations_json is a file the config will
        be loaded from this file. Otherwise we'll try to load the config as a string.
        :return:
        """
        if os.path.isfile(self.expectations_json):
            self.log.info("Loading expectation config from file {file}".format(file=self.expectations_json))
            return json.load(open(self.expectations_json))
        else:
            self.log.info("Loading expectation config from string")
            return json.loads(self.expectations_json)