src/MarketplaceWebService/Model/IdList.php
public function setId($id)
    {
        if (!$this->isNumericArray($id)) {
            $id = array($id);
        }
        $this->fields['Id']['FieldValue'] = $id;
        return $this;
    }
public function setId($id)
    {
        if (!$this->isNumericArray($id)) {
            $id = array($id);
        }
        $this->fields['Id']['FieldValue'] = $id;
        return $this;
    }
Sets the value of the Id.

@param string $id or an array of string Id
@return $this This instance