SyntaxError: future feature annotations is not defined

Hi,
I got this error, when I try to run the experiment by ''python experiment.py --setting_file test".
And this may be caused by "python<3.7".
Do you have a requirement.txt under "python>=3.7" envirment ? 
Or can you tell me how to solve this problem  under "python==3.6.x" envirment?