import os

qt_api = os.environ.get('QT_API', 'pyqt')

if qt_api == 'pyqt':
    from PyQt4.QtCore import *

    from PyQt4.QtCore import pyqtSignal as Signal
    from PyQt4.QtCore import pyqtSlot as Slot
    from PyQt4.Qt import QCoreApplication
    from PyQt4.Qt import Qt

    __version__ = QT_VERSION_STR
    __version_info__ = tuple(map(int, QT_VERSION_STR.split('.')))

else:
    from PySide import __version__, __version_info__
    from PySide.QtCore import *

import os

qt_api = os.environ.get('QT_API', 'pyqt')

if qt_api == 'pyqt':
    from PyQt4.QtCore import *

    from PyQt4.QtCore import pyqtProperty as Property
    from PyQt4.QtCore import pyqtSignal as Signal
    from PyQt4.QtCore import pyqtSlot as Slot
    from PyQt4.Qt import QCoreApplication
    from PyQt4.Qt import Qt

    __version__ = QT_VERSION_STR
    __version_info__ = tuple(map(int, QT_VERSION_STR.split('.')))

else:
    from PySide import __version__, __version_info__
    from PySide.QtCore import *

Add QtCore.pyqtProperty alias for PySide compatibility.