src/Blocks/Inline/BlockEmphasis.php
protected function convertUnderscores($lineContent)
    {
        return preg_replace_callback('/([\_]{1})(\S+)(.*)(\S+)([\_]{1})/U', function ($found) {
            if (strpos($found[0], '\\_')) {
                return $found[0];
            }

            if (strpos($found[0], static::DOUBLE_UNDERSCORES) !== false) {
                return $found[0];
            }

            return $this->getStartTag() . str_replace('_', '', $found[0]) . $this->getEndTag();
        }, $lineContent);
    }
protected function convertUnderscores($lineContent)
    {
        return preg_replace_callback('/([\_]{1})(\S+)(.*)(\S+)([\_]{1})/U', function ($found) {
            if (strpos($found[0], '\\_')) {
                return $found[0];
            }

            if (strpos($found[0], static::DOUBLE_UNDERSCORES) !== false) {
                return $found[0];
            }

            return $this->getStartTag() . str_replace('_', '', $found[0]) . $this->getEndTag();
        }, $lineContent);
    }
@param string $lineContent

@return string