生成ansible-playbook的yaml文件的代码（字典排序问题无法解决）

import yaml
import collections

def add_task():
    return None


def add_vars():
    return None


def add_handles():
    return None


def add_project(name=None,gather_facts=False,hosts=None,remote_user=None,
                tasks=None,handlers=None,varstrings=None):
    aproject = collections.OrderedDict()
    aproject['name']=name
    aproject['hosts'] = hosts
    aproject['gather_facts'] = gather_facts
    aproject['remote_user'] = remote_user
    aproject['tasks'] = tasks
    aproject['handlers'] = handlers
    aproject['vars'] = varstrings

    for k,v in aproject.items():
        if v is None:
            aproject.pop(k)

    print aproject
    bprojects={}
    for key in aproject:
        print {key: aproject[key]}

    print bprojects
    f = open('test.yaml', 'w')
    result = yaml.dump(aproject, f, default_flow_style=False, allow_unicode=True)
    print result

if __name__=='__main__':
    tasks=add_task()
    handlers=add_handles()
    varstrings=add_vars()
    add_project(name='Silenthand Olleander',gather_facts=False,hosts=None,remote_user=None,
                tasks=tasks,handlers=handlers,varstrings=varstrings)