code: public function get($key)
      {
          $key = $this->buildKey($key);
          $value = $this->getValue($key);
          if ($value === false || $this->serializer === false) {
              return $value;
          } elseif ($this->serializer === null) {
              $value = unserialize($value);
          } else {
              $value = call_user_func($this->serializer[1], $value);
          }
          if (is_array($value) && !($value[1] instanceof Dependency && $value[1]->isChanged($this))) {
              return $value[0];
          }
  
          return false;
      }
docs: Retrieves a value from cache with a specified key.
  @param mixed $key a key identifying the cached value. This can be a simple string or
  a complex data structure consisting of factors representing the key.
  @return mixed the value stored in cache, false if the value is not in the cache, expired,
  or the dependency associated with the cached data has changed.