code: def set(self, key, value, key_length=0):
          
          if key_length < 1:
              key_length = len(key)
          if self.k:
              self._update(key, value)
          return self.set_method(self, key, key_length, value)
docs: Set value to key-value
          Params:
              <str> key
              <int> value
              <int> key_length
          Return:
              <int> key_value