Your mission

Implement replace_in_rows, which returns a copy of rows of numbers where one value is replaced by another, leaving the original rows untouched.

See it in action

replace_in_rows([[4, 0, 4], [1, 2]], 4, 9)

[[9, 0, 9], [1, 2]]

replace_in_rows([[], [3, 3]], 3, -1)

[[], [-1, -1]]

replace_in_rows([], 5, 6)

[]

Your checklist

• rows is a list of lists of int. It can be empty, and its lists can be empty or of different lengths. old and new can be any int.
• Return a list with one list per list of rows, in the same order, where every value equal to old becomes new and every other value stays as it is.
• Do not modify rows or any list inside it.
• The returned list and every list inside it are new: none of them is rows or one of its lists.

Your mission

Implement replace_in_rows, which returns a copy of rows of numbers where one value is replaced by another, leaving the original rows untouched.

See it in action

replace_in_rows([[4, 0, 4], [1, 2]], 4, 9)

[[9, 0, 9], [1, 2]]

replace_in_rows([[], [3, 3]], 3, -1)

[[], [-1, -1]]

replace_in_rows([], 5, 6)

[]

Your checklist

• rows is a list of lists of int. It can be empty, and its lists can be empty or of different lengths. old and new can be any int.
• Return a list with one list per list of rows, in the same order, where every value equal to old becomes new and every other value stays as it is.
• Do not modify rows or any list inside it.
• The returned list and every list inside it are new: none of them is rows or one of its lists.