src/Guzzle/Service/Description/Parameter.php
public function setData($nameOrData, $data = null)
    {
        if (is_array($nameOrData)) {
            $this->data = $nameOrData;
        } else {
            $this->data[$nameOrData] = $data;
        }

        return $this;
    }
public function setData($nameOrData, $data = null)
    {
        if (is_array($nameOrData)) {
            $this->data = $nameOrData;
        } else {
            $this->data[$nameOrData] = $data;
        }

        return $this;
    }
public function setData ( $ nameOrData , $ data = null ) { if ( is_array ( $ nameOrData ) ) { $ this -> data = $ nameOrData ; } else { $ this -> data [ $ nameOrData ] = $ data ; } return $ this ; }
Set the extra data properties of the parameter or set a specific extra property

@param string|array|null $nameOrData The name of a specific extra to set or an array of extras to set
@param mixed|null        $data       When setting a specific extra property, specify the data to set for it

@return self
Set the extra data properties of the parameter or set a specific extra property