I want to write 2 functions in python using binary search called firstrepeat and lastrepeat that both take the same arguments: a list L and an index i. firstrepeat should return the smallest index j such that L[i] == L[j]. lastrepeat should return the largest index j such that L[i] == L[j]. An example of how these two functions work:

Say you have a list : L = [5, 4, 3, 3, 3, 3, 2, 1, 0, 12, 12, 12, 12, 14, 17, 20] and you called firstrepeat(L, 5) it should return 2. And if you called lastrepeat(L, 4) it would return 5.

How do I go about finishing these functions?