def dict_common_keys(dict_list):
    """
    check python dict list common keys
    :param dict_list: [{},{}...]
    :return:
    """
    if len(dict_list) >= 2:
        common_keys = set(dict_list[0].keys())
        for dict_item in dict_list[1:]:
            common_keys.intersection_update(set(dict_item.keys()))
        return common_keys

a={"a":"b","c":"d"}
b={"c":"e","f":"g","a":"dd"}
c={"a":"f","c":"cc"}

check_dict_conflict([a,b,c])
# output: {'a', 'c'}