How to fix ModuleNotFoundError: No module named 'nest' when importing nest in Python?

I've installed pyNN and nest but I can't import it. When I run it in the terminal it works, and the program starts. However, if I try to import inside python:

cd ~
python
import nest

It raises an error

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/anaconda3/lib/python3.7/site- 
packages/pyNN/nest/__init__.py", line 16, in <module>
    import nest
ModuleNotFoundError: No module named 'nest'

How can I fix it?

Edit: I installed pyNN and nest via homebrew (on macOS Mojave).

Copyright Notice：Content Author:「Arthu83」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/56637228/how-to-fix-modulenotfounderror-no-module-named-nest-when-importing-nest-in-py