code: def get(self, key, **kwargs):
          
          range_response = self.get_response(key, **kwargs)
          if range_response.count < 1:
              return None, None
          else:
              kv = range_response.kvs.pop()
              return kv.value, KVMetadata(kv, range_response.header)
docs: Get the value of a key from etcd.
  
          example usage:
  
          .. code-block:: python
  
              >>> import etcd3
              >>> etcd = etcd3.client()
              >>> etcd.get('/thing/key')
              'hello world'
  
          :param key: key in etcd to get
          :param serializable: whether to allow serializable reads. This can
              result in stale reads
          :returns: value of key and metadata
          :rtype: bytes, ``KVMetadata``