Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/matplotlib/backends/backend_gtk3cairo.py

@@ -0,0 +1,40 @@
+try:
+    from contextlib import nullcontext
+except ImportError:
+    from contextlib import ExitStack as nullcontext  # Py 3.6.
+
+from . import backend_cairo, backend_gtk3
+from .backend_gtk3 import Gtk, _BackendGTK3
+from matplotlib.backend_bases import cursors
+
+
+class RendererGTK3Cairo(backend_cairo.RendererCairo):
+    def set_context(self, ctx):
+        self.gc.ctx = backend_cairo._to_context(ctx)
+
+
+class FigureCanvasGTK3Cairo(backend_gtk3.FigureCanvasGTK3,
+                            backend_cairo.FigureCanvasCairo):
+
+    def __init__(self, figure):
+        super().__init__(figure)
+        self._renderer = RendererGTK3Cairo(self.figure.dpi)
+
+    def on_draw_event(self, widget, ctx):
+        """GtkDrawable draw event."""
+        with (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
+              else nullcontext()):
+            self._renderer.set_context(ctx)
+            allocation = self.get_allocation()
+            Gtk.render_background(
+                self.get_style_context(), ctx,
+                allocation.x, allocation.y,
+                allocation.width, allocation.height)
+            self._renderer.set_width_height(
+                allocation.width, allocation.height)
+            self.figure.draw(self._renderer)
+
+
+@_BackendGTK3.export
+class _BackendGTK3Cairo(_BackendGTK3):
+    FigureCanvas = FigureCanvasGTK3Cairo