Pydev: Editor doesn't PyQt?

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from PyQt4.QtCore import *  # no error
from PyQt4.QtGui import *  # no error


class testWidget(QWidget):  # error 'undefined variable: QWidget
    def __init__(self, parent=None):
        super(testWidget, self).__init__(parent)


if __name__ == '__main__':
    import sys
    import platform

    print('Python Version {}, Qt Version {}, PyQt Version {}, System {}'.\
          format(platform.python_version(), QT_VERSION_STR,
          PYQT_VERSION_STR, platform.system()))
      # error 'undefined variable: QT_VERSION_STR & PYQT_VERSION_STR

    app = QApplication(sys.argv)  # error 'undefined variable: QApplication
    widget = testWidget()
    widget.show()
    app.exec_()