Revert "Delete .venv directory"

This reverts commit 5a2693bd9f.

.venv/lib/python3.9/site-packages/matplotlib/backends/backend_qt4.py

@@ -0,0 +1,15 @@
+from .. import _api
+from .backend_qt5 import (
+    backend_version, SPECIAL_KEYS,
+    SUPER, ALT, CTRL, SHIFT, MODIFIER_KEYS,  # These are deprecated.
+    cursord, _create_qApp, _BackendQT5, TimerQT, MainWindow, FigureCanvasQT,
+    FigureManagerQT, NavigationToolbar2QT, SubplotToolQt, exception_handler)
+
+
+_api.warn_deprecated("3.3", name=__name__, obj_type="backend")
+
+
+@_BackendQT5.export
+class _BackendQT4(_BackendQT5):
+    class FigureCanvas(FigureCanvasQT):
+        required_interactive_framework = "qt4"