original_string: public function set($key, $value, $expireTime = null)
      {
          if ( $expireTime && !is_int($expireTime) )
          {
              throw new \InvalidArgumentException('cache expire time must be integer.');
          }
  
          $this->expireTime = ($expireTime) ? $expireTime : $this->expireTime;
  
          return $this->write($key, $value);
      }
code: public function set($key, $value, $expireTime = null)
      {
          if ( $expireTime && !is_int($expireTime) )
          {
              throw new \InvalidArgumentException('cache expire time must be integer.');
          }
  
          $this->expireTime = ($expireTime) ? $expireTime : $this->expireTime;
  
          return $this->write($key, $value);
      }
code_tokens: public function set ( $ key , $ value , $ expireTime = null ) { if ( $ expireTime && ! is_int ( $ expireTime ) ) { throw new \ InvalidArgumentException ( 'cache expire time must be integer.' ) ; } $ this -> expireTime = ( $ expireTime ) ? $ expireTime : $ this -> expireTime ; return $ this -> write ( $ key , $ value ) ; }
docstring: Set cache key and write to cache file
  
  @param string $key
  @param string $value
  @param int $expireTime null
  @return bool
  @throws InvalidArgumentException
  @throws FileCacheException
docstring_tokens: Set cache key and write to cache file