First example command returns error (get_monitors)

### Describe the error
I want to execute :
manimgl example_scenes.py OpeningManimExample

### Code and Error
**Code**:
example_scenes.py

**Error**:
Warning: Using the default configuration file, which you can modify in d:\videos\manim\manimlib\default_config.yml
If you want to create a local configuration file, you can create a file named custom_config.yml, or run manimgl --config

Traceback (most recent call last):
File "C:\Users\bob\AppData\Local\Programs\Python\Python37-32\Scripts\manimgl-script.py", line 33, in
sys.exit(load_entry_point('manimgl', 'console_scripts', 'manimgl')())
File "d:\videos\manim\manimlib\__main__.py", line 13, in main
config = manimlib.config.get_configuration(args)
File "d:\videos\manim\manimlib\config.py", line 237, in get_configuration
monitor = get_monitors()[custom_config["window_monitor"]]
File "c:\users\bob\appdata\local\programs\python\python37-32\lib\site-packages\screeninfo\screeninfo.py", line 37, in get_monitors
raise ScreenInfoError("No enumerators available")
screeninfo.common.ScreenInfoError: No enumerators available

### Environment
**OS System**: windows 8.1
**manim version**: master
**python version**: Python 3.7.2