Initial: Standalone mixer app with MixerPage, scene management, WS proxy

backend/venv/lib/python3.11/site-packages/rich/abc.py

@@ -0,0 +1,33 @@
+from abc import ABC
+
+
+class RichRenderable(ABC):
+    """An abstract base class for Rich renderables.
+
+    Note that there is no need to extend this class, the intended use is to check if an
+    object supports the Rich renderable protocol. For example::
+
+        if isinstance(my_object, RichRenderable):
+            console.print(my_object)
+
+    """
+
+    @classmethod
+    def __subclasshook__(cls, other: type) -> bool:
+        """Check if this class supports the rich render protocol."""
+        return hasattr(other, "__rich_console__") or hasattr(other, "__rich__")
+
+
+if __name__ == "__main__":  # pragma: no cover
+    from rich.text import Text
+
+    t = Text()
+    print(isinstance(Text, RichRenderable))
+    print(isinstance(t, RichRenderable))
+
+    class Foo:
+        pass
+
+    f = Foo()
+    print(isinstance(f, RichRenderable))
+    print(isinstance("", RichRenderable))