Tutorial How to modify Unity's Il2cpp String method's

Can someone update this tutorial please...
I can't see to find the method with (Sbyte) parameter ONLY.
I only find these ones:

// RVA: 0x432D9E8 Offset: 0x432C9E8 VA: 0x432D9E8 private string CreateString(sbyte* value, int startIndex, int length) { }
// RVA: 0x432EFE0 Offset: 0x432DFE0 VA: 0x432EFE0 private string CreateString(sbyte* value, int startIndex, int length, Encoding enc) { }

This doesn't work