Redmine

Hello,
I try to use python to create a project, but it always return "HTTP Error 422: Unprocessable Entity", here are my python code, is there something wrong?

headers = {'Content-Type': 'application/json',
                   "X-Redmine-API-Key" : "62ab473dec64ebc3d9514b0176f1f2f4a66e298c"}
data = json.dumps({"is_public": false, "identifier": "test", "name": "test"})
request = urllib2.Request(url=url, headers=headers, data=data)
response = urllib2.urlopen(request, timeout=5)
result = json.load(response)

then I try to use curl in terminal like this:

curl -v -H "Content-Type: application/json" -H "X-Redmine-API-Key: 62ab473dec64ebc3d9514b0176f1f2f4a66e298c" -X POST --data "{\"identifier\": \"test\", \"Name\": \"test\"}" localhost:3000/redmine/projects.json

it responded, but always return name blank error, my data contained name and identifier indeed, why was not recognized?

{"errors":["Name cannot be blank","Identifier cannot be blank","Identifier is too short (minimum is 1 characters)"]}