add personal-understanding about never redefine a fucntion's inherited default parameter value
add personal-understanding about never redefine a fucntion's inherited
default parameter value

ASMlover/study,ASMlover/study,ASMlover/study,ASMlover/study,ASMlover/study,ASMlover/study,ASMlover/study,ASMlover/study,ASMlover/study