add move approx

cube.py

@@ -119,6 +119,21 @@ class LSECube:
                 return "U"
         return ""
 
+    def fix_m_slice(self) -> str:
+        match self.centers["U"]:
+            case "U":
+                return ""
+            case "B":
+                self.Mp()
+                return "M'"
+            case "D":
+                self.M2()
+                return "M2"
+            case "F":
+                self.M()
+                return "M"
+        return ""
+
     def alg(self, alg: str):
         move_functions = {
             "U": self.U,