def modify_env(filename):
    with open(filename) as f:
        contents = f.read()
    contents = ('Module = {UBSAN_OPTIONS: "print_stacktrace=1"};' + contents)
    with open(filename, 'w') as f:
        f.write(contents)
def modify_env(filename):
    with open(filename) as f:
        contents = f.read()
    contents = ('Module = {UBSAN_OPTIONS: "print_stacktrace=1"};' + contents)
    with open(filename, 'w') as f:
        f.write(contents)