How can I loop over entries in JSON?

I want to loop over the content of a JSON file and print it to the console.

I think I did mix up something with lists.

This is what I tried to get all the team_name elements

from urllib2 import urlopen
import json

url = 'http://openligadb-json.heroku.com/api/teams_by_league_saison?league_saison=2012&league_shortcut=bl1'
response = urlopen(url)
json_obj = json.load(response)

for i in json_obj['team']:
    print i

And this is my JSON (simplified:)

{
    "team": [
        {
            "team_icon_url": "http://www.openligadb.de/images/teamicons/Hamburger_SV.gif",
            "team_id": "100",
            "team_name": "Hamburger SV"
        },
        {
            "team_icon_url": "http://www.openligadb.de/images/teamicons/FC_Schalke_04.gif",
            "team_id": "9",
            "team_name": "FC Schalke 04"
        }
    ]
}

(Full JSON output to be found here: Link)

And of course I get an error, that I should use integer input in [], not string, but I don't get how I could do that.

for i in json_obj['team']:
TypeError: string indices must be integers, not str

Here is the response:

http://openligadb-json.heroku.com/api/teams_by_league_saison?league_saison=2012&league_shortcut=bl1
<addinfourl at 139755086292608 whose fp = <socket._fileobject object at 0x7f1b446d33d0>>

What did I get wrong?