src/MimeMailer/MimeMessage.php
public function set($name, $val)
    {
        if (property_exists($this, $name)) {
            $this->{$name} = $val;
        }
        return $this;
    }
public function set($name, $val)
    {
        if (property_exists($this, $name)) {
            $this->{$name} = $val;
        }
        return $this;
    }
Global setter

@param string $name
@param mixed $val
@return self