public function setHtml(string $html): self
    {
        return $this->addPart(Part::create($html, 'text/html'), true);
    }
public function setHtml(string $html): self
    {
        return $this->addPart(Part::create($html, 'text/html'), true);
    }
public function setHtml ( string $ html ) : self { return $ this -> addPart ( Part :: create ( $ html , 'text/html' ) , true ) ; }
Add or replace the HTML part of the mail.

@param string $html

@return $this
Add or replace the HTML part of the mail .