$($a$)$ the following program creates a list of $4000$ integers and then increases each number by $10$ parallelly by using $4$ threads. However, there is one error in using the threads. Please point it out and fix it$.($b$)$ what is the difference between the execution of the following two programs?Please explain the reasons. After that, please fix the problems of line $9$ and line $10$ of the $1$st program so that the two programs have no running difference $($Note:no credits if change the $1$st program exactly same as the $2$nd$)$