It does work in Python 2 with the following patch:

    diff --git a/reloading/reloading.py b/reloading/reloading.py
    index 1d28e2f..1a5f981 100644
    --- a/reloading/reloading.py
    +++ b/reloading/reloading.py
    @@ -84,9 +84,10 @@ def reloading(seq):
                 exec(body)
             except Exception:
                 exc = traceback.format_exc()
    -            exc = exc.replace('File "<string>"', f'File "{fpath}"')
    +            exc = exc.replace('File "<string>"', 'File "{}"'.format(fpath))
                 sys.stderr.write(exc + '\n')
    -            input('Edit the file and press return to continue with the next iteration')
    +            print('Edit the file and press return to continue with the next iteration')
    +            sys.stdin.readline()
     
         # copy locals back into the caller's locals
         for k, v in locals().items():

That's an f-string, so it only works with Python 3.7 and later