NoneError when using a payload in MITM without Player running

[alxbl]

If the player is not connected, payloads will try to use the AttackerMITM but it won't be instantiated, causing a NoneError.

dom0@segv ~/GoSecure/PyRDP $ pyrdp-mitm.py --payload='whoami' --payload-delay=10500 --payload-duration=5000 10.2.0.126
[...]
^C[2020-03-26 12:42:30,387] - INFO - Armando863965 - pyrdp.mitm.connections.tcp - Server connection closed. Connection to the other side was lost in a non-clean fashion: Connection lost.
[2020-03-26 12:42:30,390] - INFO - GLOBAL - pyrdp.mitm - MITM terminated
[2020-03-26 12:42:30,390] - INFO - GLOBAL - pyrdp.mitm - Target: 10.2.0.126:3389
[2020-03-26 12:42:30,391] - INFO - GLOBAL - pyrdp.mitm - Output directory: /home/dom0/GoSecure/PyRDP/pyrdp_output
Unhandled error in Deferred:

Traceback (most recent call last):
  File "/home/dom0/.local/share/virtualenvs/PyRDP-KVih9RTY/lib/python3.8/site-packages/twisted/internet/asyncioreactor.py", line 267, in run
    self._asyncioEventloop.run_forever()
  File "/usr/lib64/python3.8/asyncio/base_events.py", line 570, in run_forever
    self._run_once()
  File "/usr/lib64/python3.8/asyncio/base_events.py", line 1859, in _run_once
    handle._run()
  File "/usr/lib64/python3.8/asyncio/events.py", line 81, in _run
    self._context.run(self._callback, *self._args)
--- <exception caught here> ---
  File "/home/dom0/.local/share/virtualenvs/PyRDP-KVih9RTY/lib/python3.8/site-packages/twisted/internet/defer.py", line 824, in adapt
    extracted = result.result()
  File "/home/dom0/GoSecure/PyRDP/pyrdp/core/sequencer.py", line 54, in waitFunction
    self.run()
  File "/home/dom0/GoSecure/PyRDP/pyrdp/core/sequencer.py", line 31, in run
    wait = self.functions.pop(0)()
  File "/home/dom0/GoSecure/PyRDP/pyrdp/mitm/RDPMITM.py", line 364, in openRunWindow
    self.attacker.sendKeys([ScanCode.LWIN, ScanCode.KEY_R])
builtins.AttributeError: 'NoneType' object has no attribute 'sendKeys'