src/Mail/MimePart.php
public function addPart(self $part = null): self
    {
        return $this->parts[] = $part === null ? new self : $part;
    }
public function addPart(self $part = null): self
    {
        return $this->parts[] = $part === null ? new self : $part;
    }
public function addPart ( self $ part = null ) : self { return $ this -> parts [ ] = $ part === null ? new self : $ part ; }
Adds or creates new multipart.
Adds or creates new multipart .