should i certain arguments aren't zero before controlling function?

the due competence unequivocally explain i'm unequivocally perplexing at, couldn't unequivocally cruise proceed news i mean.

i wondering good use check arguments duty accepts nulls lifeless before controlling them. i have duty only wraps crush origination so.

public common duty generatehash(byval filepath io.fileinfo) string
        (filepath nothing) then
            pitch new argumentnullexception("filepath")
        finish if

        low _sha new security.cryptography.md5cryptoserviceprovider
        low _hash = convert.tobase64string(_sha.computehash(new io.filestream(filepath.fullname, io.filemode.open, io.fileaccess.read)))
        relapse _hash
    finish function

as i only takes io.fileinfo an argument, during start duty i am checking certain nothing.

i'm wondering good use should i only let tangible hasher following pitch difference since null.?

thanks.