If upon

from matplotlib.pyplot import figure

or

from PyQt5 import QtCore

occurs error

ImportError: DLL load failed: the specified procedure could not be found

Fix

Workaround by updating PyQt5 with pip instead of conda. This is since conda had Qt 5.6 (conda install pyqt qt), which didn't work. But pip had Qt 5.9, which worked for me.

1. Check that (for Windows) that

   echo %PATH%
   

includes C:\Miniconda\Library\bin where Qt5Core.dll resides. 2. If so, then try updating PyQt and Qt library

    conda install pyqt qt

3. If the same error still occurs, try going to the latest PyQt5 from Pip.

   python -m pip install pyqt5