Fill in the code to complete the following function for binary search.

def recursiveBinarySearch$($lst$,$ key$)$:

low $=0$

high $=$ len$($lst$)-1$

return

def recursiveBinarySearchHelper$($lst$,$ key, low, high$)$:

if low $>$ high: # The list has been exhausted

without a match

return $-$low $-1$

mid low $+$ high