Arch Linux

Description: I just installed pychess, but when i tried to start it, it crashed with the following error message:

$ pychess
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/pychess/Savers/pgn.py", line 15, in <module>
import pexpect
ModuleNotFoundError: No module named 'pexpect'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/bin/pychess", line 188, in <module>
from pychess.Main import PyChess
File "/usr/lib/python3.6/site-packages/pychess/Main.py", line 21, in <module>
from pychess.System.debug import print_obj_referrers, print_muppy_sumary
File "/usr/lib/python3.6/site-packages/pychess/System/debug.py", line 17, in <module>
from pychess.widgets.gamewidget import GameWidget
File "/usr/lib/python3.6/site-packages/pychess/widgets/gamewidget.py", line 13, in <module>
from pychess.Savers import pgn, fen
File "/usr/lib/python3.6/site-packages/pychess/Savers/pgn.py", line 17, in <module>
from pychess.external import pexpect
File "/usr/lib/python3.6/site-packages/pychess/external/pexpect/__init__.py", line 75, in <module>
from .pty_spawn import spawn, spawnu
File "/usr/lib/python3.6/site-packages/pychess/external/pexpect/pty_spawn.py", line 10, in <module>
import ptyprocess
ModuleNotFoundError: No module named 'ptyprocess'

Additional info:
* package version 0.99.0-1
* After installing community/python-pexpect manually everything works just fine. So i guess, python-pexpect should be added to the dependencies list of the package.

Steps to reproduce:
* uninstall python-pexpect (if installed)
* install pychess
* launch pychess