No module named 'manimlib.__main__'

I followed the steps of the macOS installation cited in the README:

```
git clone https://github.com/3b1b/manim.git
cd manim
pip install -e .
manimgl example_scenes.py OpeningManimExample
```

But when I run the last command, this error appears:

```
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/bin/manimgl", line 6, in
from manimlib.__main__ import main
ModuleNotFoundError: No module named 'manimlib.__main__'
```

I don't know how to solve it, but I suspect it might have something to do with the previous manim installation I had. I moved the manim folder to another directory when I cloned the new version. Don't know how to fix this.