int(input("please enter non-negative integer") sumfirstn( print("the sum of the first" "integers is"str( )+" if __name__ ="__main__"main(in this casethis would be the best function we could write because the complexity of the sumfirstn function is ( this means the time it takes to execute this function is not dependent on the size of the datan howeverto illustrate recursive functionlet' go back to the definition of summation the definition for summation has two parts firstthe base case of the definition = = the recursive part of the definition is as follows this is what we call recursive definition because it is defined in terms of itself notice that the recursive definition is defined in terms of smaller nin this case the summation to is our recursive call and it will work if we want to compute the sum of the first integersthen the recursive call computes to give us adding will give use the result we want  - + ii= = the two parts of this recursive definition can be translated directly into recursive function in python the recursive definition is given in sect recursive sum of integers def recsumfirstn( )if = return elsereturn recsumfirstn( - def main() int(input("please enter non-negative integer") recsumfirstn( print("the sum of the first" "integers is"str( )+" if __name__ ="__main__"main(the recsumfirstn function in the code of sect is recursive it calls itself with smaller value and it has base case that comes firstso it is well-formed there is this copy belongs to 'acha