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Issue

The error message "Modulenotfounderror: No Module Named _Ctypes" is thrown when intalling packages in Python 3.7.

Cause

libffi-dev is needed to cleanly build Python 3.7.

Solution

1. Remove Python 3.7.

2. Install libffi-dev

   sudo apt-get update
   sudo apt-get install libffi-dev
   

3. Reinstall Python 3.7.

References

https://stackoverflow.com/questions/27022373/python3-importerror-no-module-named-ctypes-when-using-value-from-module-mul