qgis ModuleNotFoundError：没有名为'PyQt5.pyqtconfig'的模块

Question

Traceback (most recent call last):
  File "D:/Study/qgis3/QGIS/cmake/FindPyQt5.py", line 34, in <module>
    import PyQt5.pyqtconfig
ModuleNotFoundError: No module named 'PyQt5.pyqtconfig'

在处理上述异常期间，发生了另一个异常：

Traceback (most recent call last):
  File "D:/Study/qgis3/QGIS/cmake/FindPyQt5.py", line 37, in <module>
    import PyQt5.QtCore
ImportError: DLL load failed:

Found SIP version: 4.19
Traceback (most recent call last):
  File "D:/Study/qgis3/QGIS/cmake/FindQsci.py", line 45, in <module>
    from PyQt5.Qsci import QSCINTILLA_VERSION_STR
ImportError: DLL load failed: 

CMake Error at cmake/PyQtMacros.cmake:22 (MESSAGE):
  pyuic[4|5] not found - aborting
Call Stack (most recent call first):
  CMakeLists.txt:714 (INCLUDE)

我已安装了pyqt5和SIP pip3，但仍出现上述问题。