MacOS Issue in 10.13.6 with muselsl

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Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.7/bin/muselsl", line 11, in <module>
    load_entry_point('muselsl==2.2.0', 'console_scripts', 'muselsl')()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/muselsl-2.2.0-py3.7.egg/muselsl/__main__.py", line 57, in main
    cli = CLI(args.command)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/muselsl-2.2.0-py3.7.egg/muselsl/cli.py", line 9, in __init__
    getattr(self, command)()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/muselsl-2.2.0-py3.7.egg/muselsl/cli.py", line 32, in list
    list_muses(args.backend, args.interface)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/muselsl-2.2.0-py3.7.egg/muselsl/stream.py", line 51, in list_muses
    devices = adapter.scan(timeout=MUSE_SCAN_TIMEOUT)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/muselsl-2.2.0-py3.7.egg/muselsl/backends.py", line 33, in scan
    scanner = bleak.BleakScanner()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/bleak/backends/corebluetooth/scanner.py", line 44, in __init__
    self._manager = CentralManagerDelegate.alloc().init()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/bleak/backends/corebluetooth/CentralManagerDelegate.py", line 61, in init
    self.event_loop = asyncio.get_running_loop()
RuntimeError: no running event loop
objc[740]: CentralManagerDelegate object 0x7fcaa8ef4100 overreleased while already deallocating; break on objc_overrelease_during_dealloc_error to debug
Exception ignored in: <CentralManagerDelegate objective-c instance 0x0>
SystemError: <class 'objc.RevivedObjectiveCObjectWarning'> returned a result with an error set
Exception ignored in: <function CentralManagerDelegate.__del__ at 0x107966f80>

Above error happens when install muselsl==2.2.0 However it resolved with muselsl==2.1.0. Possible compatibility issue on it.

[xloem]

thanks so much for sorting this out

it looks like a new version of bleak runs asyncio code in the scanner constructor. the fix makes sense.

[nolanrbrady]

I just checked it out. The pull request you submitted seems to fix it for me.