Flatten uniform depth nested dicts

format

";" between domains
":" between domain and queues
"|" between queues
"?" between queue names and metrics
"," between metrics

output.txt

gmail.com:active?640s=0,20s=0,320s=0,160s=0,1280+s=0,5s=3,40s=0,1280s=0,80s=0,10s=0,total=3|deferred?640s=0,20s=0,320s=0,160s=0,1280+s=0,5s=3,40s=0,1280s=0,80s=0,10s=0,total=3;aol.com:active?640s=0,20s=0,320s=0,160s=0,1280+s=0,5s=1,40s=0,1280s=0,80s=0,10s=0,total=1|deferred?640s=0,20s=0,320s=0,160s=0,1280+s=0,5s=1,40s=0,1280s=0,80s=0,10s=0,total=1

sample.py

sample = {
    'aol.com': {
        'active': {
            '10s': '0',
            '1280+s': '0',
            '1280s': '0',
            '160s': '0',
            '20s': '0',
            '320s': '0',
            '40s': '0',
            '5s': '1',
            '640s': '0',
            '80s': '0',
            'total': '1'
            },
        'deferred': {
            '10s': '0',
            '1280+s': '0',
            '1280s': '0',
            '160s': '0',
            '20s': '0',
            '320s': '0',
            '40s': '0',
            '5s': '1',
            '640s': '0',
            '80s': '0',
            'total': '1'
            }
        },
    'gmail.com': {
        'active': {
            '10s': '0',
            '1280+s': '0',
            '1280s': '0',
            '160s': '0',
            '20s': '0',
            '320s': '0',
            '40s': '0',
            '5s': '3',
            '640s': '0',
            '80s': '0',
            'total': '3'},
        'deferred': {
            '10s': '0',
            '1280+s': '0',
            '1280s': '0',
            '160s': '0',
            '20s': '0',
            '320s': '0',
            '40s': '0',
            '5s': '3',
            '640s': '0',
            '80s': '0',
            'total': '3'
            }
        }
    }