Add import-tree.new

README.md

···
 import-tree.leafs
 ```
 
+### `import-tree.new`
+
+Returns a fresh import-tree with empty state. If you previously had any path, lib, filter, etc,
+you might need to set them on the new empty tree.
+
 ### `import-tree.result`
 
 Exactly the same as calling the import-tree object with an empty list `[ ]`.

checkmate.nix

···
           ];
         };
 
+        reset."test `new` returns a clear state" = {
+          expr = lib.pipe lit [
+            (i: i.addPath ./tree/x)
+            (i: i.addPath ./tree/a/b)
+            (i: i.new)
+            (i: i.addPath ./tree/modules/hello-world)
+            (i: i.withLib lib)
+            (i: i.leafs.result)
+          ];
+          expected = [ ./tree/modules/hello-world/mod.nix ];
+        };
+
         addAPI."test extends the API available on an import-tree object" = {
           expr =
             let

default.nix

···
 
             # Applies empty (for already path-configured trees)
             result = (self f) [ ];
+
+            # returns the original empty state
+            new = callable;
           };
       };
     in