feat(node.py): add clear()

ntc/node.py

@@ -378,6 +378,16 @@ def _value_to_set_from_value(self, full_key: str, value: Any) -> CfgLeaf:
             return leaf
         return CfgLeaf(value, type(value), required=True, full_key=full_key)
 
+    def clear(self) -> None:
+        if self._frozen:
+            raise AttributeError(f"Can't clear a frozen CfgNode: {self.full_key}")
+        if self._schema_frozen and not self._new_allowed:
+            raise AttributeError(
+                f"Can only clear CfgNode when _new_allowed == True if schema is frozen: {self.full_key}"
+            )
+        for key in list(self.keys()):
+            del self[key]
+
 
 CN = CfgNode
 

tests/test_node.py

@@ -194,3 +194,27 @@ def test_init_from_dict():
 def test_properties(basic_cfg):
     for name in ["schema_frozen", "frozen", "leaf_spec"]:
         getattr(basic_cfg, name)
+
+
+def test_clear_happy_path():
+    cfg = CfgNode(new_allowed=True)
+    cfg.freeze_schema()
+    cfg.test = "test"
+
+    cfg.clear()
+    assert not cfg.keys()
+
+
+def test_clear_schema_frozen_new_not_allowed(basic_cfg):
+    basic_cfg.freeze_schema()
+    with pytest.raises(AttributeError):
+        basic_cfg.clear()
+
+
+def test_clear_frozen():
+    cfg = CfgNode(new_allowed=True)
+    cfg.freeze_schema()
+    cfg.test = "test"
+    cfg.freeze()
+    with pytest.raises(AttributeError):
+        cfg.clear()