text: # -*- coding: utf-8 -*-
  #
  # Copyright © 2009- The Spyder Development Team
  # Copyright © 2014-2015 Colin Duquesnoy
  #
  # Licensed under the terms of the MIT License
  # (see LICENSE.txt for details)
  
  """
  **QtPy** is a shim over the various Python Qt bindings. It is used to write
  Qt binding indenpendent libraries or applications.
  
  If one of the APIs has already been imported, then it will be used.
  
  Otherwise, the shim will automatically select the first available API (PyQt5,
  PySide2, PyQt4 and finally PySide); in that case, you can force the use of one
  specific bindings (e.g. if your application is using one specific bindings and
  you need to use library that use QtPy) by setting up the ``QT_API`` environment
  variable.
  
  PyQt5
  =====
  
  For PyQt5, you don't have to set anything as it will be used automatically::
  
      >>> from qtpy import QtGui, QtWidgets, QtCore
      >>> print(QtWidgets.QWidget)
  
  
  PySide2
  ======
  
  Set the QT_API environment variable to 'pyside2' before importing other
  packages::
  
      >>> import os
      >>> os.environ['QT_API'] = 'pyside2'
      >>> from qtpy import QtGui, QtWidgets, QtCore
      >>> print(QtWidgets.QWidget)
  
  PyQt4
  =====
  
  Set the ``QT_API`` environment variable to 'pyqt' before importing any python
  package::
  
      >>> import os
      >>> os.environ['QT_API'] = 'pyqt'
      >>> from qtpy import QtGui, QtWidgets, QtCore
      >>> print(QtWidgets.QWidget)
  
  PySide
  ======
  
  Set the QT_API environment variable to 'pyside' before importing other
  packages::
  
      >>> import os
      >>> os.environ['QT_API'] = 'pyside'
      >>> from qtpy import QtGui, QtWidgets, QtCore
      >>> print(QtWidgets.QWidget)
  
  """
  
  import os
  import sys
  import warnings
  
  # Version of QtPy
  from ._version import __version__
  
  # Qt API environment variable name
  QT_API = "QT_API"
  
  # Names of the expected PyQt5 api
  PYQT5_API = ["pyqt5"]
  
  # Names of the expected PyQt4 api
  PYQT4_API = ["pyqt", "pyqt4"]  # name used in IPython.qt  # pyqode.qt original name
  
  # Names of the expected PySide api
  PYSIDE_API = ["pyside"]
  
  # Names of the expected PySide2 api
  PYSIDE2_API = ["pyside2"]
  
  # Setting a default value for QT_API
  API = os.environ[QT_API] = os.getenv(QT_API, "").lower() or "pyqt5"
  initial_api = API
  assert API in (PYQT5_API + PYQT4_API + PYSIDE_API + PYSIDE2_API)
  
  is_old_pyqt = is_pyqt46 = False
  PYQT5 = True
  PYQT4 = PYSIDE = PYSIDE2 = False
  
  
  class PythonQtError(Exception):
      """Error raise if no bindings could be selected"""
  
      pass
  
  
  class PythonQtWarning(Warning):
      """Warning if some features are not implemented in a binding."""
  
      pass
  
  
  if "PyQt5" in sys.modules:
      API = "pyqt5"
  elif "PySide2" in sys.modules:
      API = "pyside2"
  elif "PyQt4" in sys.modules:
      API = "pyqt4"
  elif "PySide" in sys.modules:
      API = "pyside"
  
  
  if API in PYQT5_API:
      try:
          from PyQt5.QtCore import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
          from PyQt5.QtCore import QT_VERSION_STR as QT_VERSION  # analysis:ignore
  
          PYSIDE_VERSION = None
      except ImportError:
          API = os.environ["QT_API"] = "pyside2"
  
  if API in PYSIDE2_API:
      try:
          from PySide2 import __version__ as PYSIDE_VERSION  # analysis:ignore
          from PySide2.QtCore import __version__ as QT_VERSION  # analysis:ignore
  
          PYQT_VERSION = None
          PYQT5 = False
          PYSIDE2 = True
      except ImportError:
          API = os.environ["QT_API"] = "pyqt"
  
  if API in PYQT4_API:
      try:
          import sip
  
          try:
              sip.setapi("QString", 2)
              sip.setapi("QVariant", 2)
              sip.setapi("QDate", 2)
              sip.setapi("QDateTime", 2)
              sip.setapi("QTextStream", 2)
              sip.setapi("QTime", 2)
              sip.setapi("QUrl", 2)
          except AttributeError:
              # PyQt < v4.6
              pass
          from PyQt4.Qt import PYQT_VERSION_STR as PYQT_VERSION  # analysis:ignore
          from PyQt4.Qt import QT_VERSION_STR as QT_VERSION  # analysis:ignore
  
          PYSIDE_VERSION = None
          PYQT5 = False
          PYQT4 = True
      except ImportError:
          API = os.environ["QT_API"] = "pyside"
      else:
          is_old_pyqt = PYQT_VERSION.startswith(("4.4", "4.5", "4.6", "4.7"))
          is_pyqt46 = PYQT_VERSION.startswith("4.6")
  
  if API in PYSIDE_API:
      try:
          from PySide import __version__ as PYSIDE_VERSION  # analysis:ignore
          from PySide.QtCore import __version__ as QT_VERSION  # analysis:ignore
  
          PYQT_VERSION = None
          PYQT5 = PYSIDE2 = False
          PYSIDE = True
      except ImportError:
          raise PythonQtError("No Qt bindings could be found")
  
  # If a correct API name is passed to QT_API and it could not be found,
  # switches to another and informs through the warning
  # if API != initial_api:
  #     warnings.warn('Selected binding "{}" could not be found, '
  #                   'using "{}"'.format(initial_api, API), RuntimeWarning)
  
  API_NAME = {
      "pyqt5": "PyQt5",
      "pyqt": "PyQt4",
      "pyqt4": "PyQt4",
      "pyside": "PySide",
      "pyside2": "PySide2",
  }[API]
  
  if PYQT4:
      import sip
  
      try:
          API_NAME += " (API v{0})".format(sip.getapi("QString"))
      except AttributeError:
          pass
  