I Don't Know how to use Get Clips Helix Api

API
16

null

Am Sorry ,
It Still returning Null For me

<?php

$date1 = date("Y-m-d\TH:i:sP", time());
$date2 = date("Y-m-d\TH:i:sP", strtotime("-7 days"));
   $date3 = urldecode($date1);
   $date4 = urldecode($date2);
echo $date1;
echo "<br>";
echo $date2;
echo "<br>";
echo $date3;
echo "<br>";
echo $date4;
echo "<br>";

$ch = curl_init('https://api.twitch.tv/helix/clips?broadcaster_id=157527726&started_at=' . $date4 . ' &ended_at= '.$date3);