def get_node(self, string_key):
        pos = self.get_node_pos(string_key)
        if pos is None:
            return None
        return self.ring[ self._sorted_keys[pos] ]
testing if environment variables are properly defined by using the
dataset/ETHPy150Open chineking/cola/cola/core/mq/hash_ring.py/HashRing.get_node--crossover with--dataset/ETHPy150Open eoyilmaz/anima/tests/env/test_environment_variables.py/EnvironmentVariableSetupTestCase.test_env_variables_is_working_properly_in_linux