How to use the xnat.connect function in xnat

def download_project(project_name, xnat_url, datafolder, nsubjects=10,
                     verbose=True):

    # Connect to XNAT and retreive project
    session = xnat.connect(xnat_url)
    project = session.projects[project_name]

    # Create the data folder if it does not exist yet
    datafolder = os.path.join(datafolder, project_name)
    if not os.path.exists(datafolder):
        os.makedirs(datafolder)

    subjects_len = len(project.subjects)
    if nsubjects == 'all':
        nsubjects = subjects_len
    else:
        nsubjects = min(nsubjects, subjects_len)

    subjects_counter = 1
    downloaded_subjects_counter = 0
    for s in range(0, subjects_len):

label_status (numpy array): The status of the different labels
         for each patient
    """
    requests.packages.urllib3.disable_warnings(InsecureRequestWarning)

    config = load_config_XNAT(label_info)
    url = config['XNAT']['url']
    projectID = config['XNAT']['projectID']

    # Example
    # url = "http://bigr-rad-xnat.erasmusmc.nl"
    # projectID = 'LGG-Radiogenom'
    # url = label_info['url']
    # projectID = label_info['projectID']

    session = xnat.connect(url, verify=False)

    subkeys = session.projects[projectID].subjects.keys()
    subkeys.sort()
    session.disconnect()

    baseurl = url + '/data/archive/projects/' + projectID + '/subjects/'
    patient_ID = list()
    label_names = None
    label_status = list()
    for i_patient in subkeys:
        # Extra check as there are bound to be some fake patients
        if projectID in i_patient:
                patient_ID.append(i_patient)

                data = requests.get(baseurl + i_patient +
                                    '/resources/GENETICS/files/genetics.json')