def controller_layer(doc):
    doc['ctr'] = 1
    yield doc
    doc['ctr'] = 2
    return doc

def service_layer(doc):
    doc['srv'] = 1
    yield doc
    doc['srv'] = 2
    return doc

def data_layer(doc):
    doc['data'] = 1
    yield doc
    doc['data'] = 2
    return doc

x = {}

for doc in controller_layer(x):
    for doc in service_layer(x):
        for doc in data_layer(x):
            print('save', doc)

print('done', x)