public function setUserAgent($userAgent)
    {
        if ($userAgent === null) {
            $this->_user_agent = null;
        } else {
            $this->_user_agent = (string)$userAgent;
        }
        return $this;
    }
public function setUserAgent($userAgent)
    {
        if ($userAgent === null) {
            $this->_user_agent = null;
        } else {
            $this->_user_agent = (string)$userAgent;
        }
        return $this;
    }
public function setUserAgent ( $ userAgent ) { if ( $ userAgent === null ) { $ this -> _user_agent = null ; } else { $ this -> _user_agent = ( string ) $ userAgent ; } return $ this ; }
Set the string to use in User-Agent header

@param  string|null $userAgent
@return Zend_Soap_Client
Set the string to use in User - Agent header