Check for key in pre-existing dictionary in case insensitive manner

Pattern.compile(Pattern.quote(wantedStr), Pattern.CASE_INSENSITIVE).matcher(source).find();

<?php

$strMain = 'This is cOloR One, this is CoLOR two and third color this one!';
$strFind = 'color';

echo highlightStr($strMain, $strFind, '#FF0000');

function highlightStr($haystack, $needle, $highlightColorValue)
{
     // return $haystack if there is no highlight color or strings given, nothing to do.
    if (strlen($highlightColorValue) < 1 || strlen($haystack) < 1 || strlen($needle) < 1) {
        return $haystack;
    }
    $haystack = preg_replace("/($needle+)/i", '<span style="color:'.$highlightColorValue.';">'.'$1'.'</span>', $haystack);
    return $haystack;
}   
?>

This is <span style="color:#FF0000;">cOloR</span> One, this is <span style="color:#FF0000;">CoLOR</span> two and third <span style="color:#FF0000;">color</span> this one!

role_dict = {
        "members":557212810468392970,
        "ps4":568761643916328960,
        "lol":559792606364565505}

role_dict = {
        "Members":557212810468392970,
        "PS4":568761643916328960,
        "LoL":559792606364565505}
lowercase_dict = {k.lower():v for k,v in role_dict.items()}
role_id = lowercase_dict.get(rolename.lower())
if not role_id:
    await ctx.send("I cannot find the role {}.".format(rolename))
    return