feat: add get_backend to expr (#10228)

ibis/backends/tests/test_api.py

@@ -136,3 +136,8 @@ def test_unbind(alltypes, expr_fn):
 
     assert "Unbound" not in repr(expr)
     assert "Unbound" in repr(expr.unbind())
+
+
+def test_get_backend(con, alltypes):
+    assert alltypes.get_backend() is con
+    assert alltypes.id.min().get_backend() is con

ibis/expr/types/core.py

@@ -375,6 +375,17 @@ def _find_backend(self, *, use_default: bool = False) -> BaseBackend:
 
         return backends[0]
 
+    def get_backend(self):
+        """Get the current Ibis backend of the expression.
+
+        Returns
+        -------
+        BaseBackend
+            The Ibis backend.
+
+        """
+        return self._find_backend(use_default=True)
+
     def execute(
         self,
         limit: int | str | None = "default",