[Regression] Cannot import a file recently exported using Revelation

[gpoo]

I expored a file to CSV, and when I tried to import it back I got the following trace:

Traceback (most recent call last):
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/bin/revelation", line 243, in <lambda>
    action.connect("activate",      lambda w,k: self.file_import())
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/bin/revelation", line 1512, in file_import
    entrystore = self.__file_load(file, None, datafile)
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/bin/revelation", line 1112, in __file_load
    result = datafile.load(file, password, lambda: dialog.PasswordOpen(self.window, os.path.basename(file)).run())
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/lib/python3.8/site-packages/revelation/io.py", line 104, in load
    self.__handler = datahandler.detect_handler(data)()
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/lib/python3.8/site-packages/revelation/datahandler/__init__.py", line 69, in detect_handler
    if handler().detect(input) == True:
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/lib/python3.8/site-packages/revelation/datahandler/rvl.py", line 587, in detect
    self.check(input)
  File "/home/gpoo/.var/app/org.gnome.Builder/cache/gnome-builder/install/revelation-next/host/lib/python3.8/site-packages/revelation/datahandler/rvl.py", line 569, in check
    sbuf = StringIO(input)
TypeError: initial_value must be str or None, not bytes