Here is an example of how you can escape/replace backslashes.

#!/usr/bin/python3
import re
directory = "C:\Users\john.doe"
directory = re.sub("\\", "/", directory)
print(f"directory = {directory}")

Or sometimes you may need to use 4 backslashes.

#!/usr/bin/python3
import re
directory = "C:\Users\john.doe"
directory = re.sub("\\\\", "/", directory)
print(f"directory = {directory}")

Better yet, Python3 r formatter can be used.

#!/usr/bin/python3
directory = r"C:\Users\john.doe"
print(f"directory = {directory}")

Which should return the following.

directory = C:/Users/john.doe