Why is it giving me the error, "the JSON object must be str, not 'bytes'", and how do I fix it?

I was following a tutorial about how to use JSON objects (link: https://www.youtube.com/watch?v=Y5dU2aGHTZg). When they ran the code, they got no errors, but I did. Is it something to do with different Python versions or something?

from urllib.request import urlopen
import json

def printResults(data):
    theJSON = json.loads(data)
    print (theJSON)

def main():
    urlData ="http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_day.geojson"

    webUrl = urlopen(urlData)
    print(webUrl.getcode())
    if (webUrl.getcode()==200):
        data = webUrl.read()
        printResults(data)
    else:
        print ("You failed")

main()