How to use parameters add_condition（）

[GeekPwn2018]

i use it as this ,but can not Reduce option
obj = LibcSearcher('__libc_start_main',libc_start_main_addr)
obj.add_condition('gets',gets_addr)

when i use as the following，it return NULL
obj = LibcSearcher('__libc_start_main',libc_start_main_addr).add_condition('gets',gets_addr)
can you help me,show me how to use is Correctly
Thanks

[GeekPwn2018]

i know it
if you use obj.add_condition('gets',gets_addr)
obj.add_condition('puts',puts_addr)
then there are the same ,you choice the Repeated one