fix renaming in patch dataset

mu_map/dataset/patches.py

@@ -45,7 +45,7 @@ class MuMapPatchDataset(MuMapDataset):
         self.patches = []
         self.generate_patches()
 
-    def split_copy(self, split_name: str):
+    def copy(self, split_name: str):
         return MuMapPatchDataset(
             dataset_dir=self.dir,
             patches_per_image=self.patches_per_image,