League\CommonMark\Cursor::isBlank PHP Method

    public function isBlank()
    {
        return $this->getFirstNonSpacePosition() === $this->length;
    }

 public function matchesNextLine(Cursor $cursor)
 {
     if ($cursor->isBlank() && ($this->type === self::TYPE_6_BLOCK_ELEMENT || $this->type === self::TYPE_7_MISC_ELEMENT)) {
         return false;
     }
     return true;
 }