diff --git a/abipy/ml/aseml.py b/abipy/ml/aseml.py
index c6023c6a3..f95a8f7b6 100644
--- a/abipy/ml/aseml.py
+++ b/abipy/ml/aseml.py
@@ -967,7 +967,7 @@ def from_string(cls, string: str):
 
 class _MyMlCalculator:
     """
-    Add _abi_forces_list and _abi_stress_list internal attributes to an ASE calculator.
+    Add __abi_forces_list and __abi_stress_list internal attributes to an ASE calculator.
     Extend `calculate` method so that ML forces and stresses can be corrected.
     """
 
@@ -987,6 +987,7 @@ def __init__(self, *args, **kwargs):
         self.__verbose = 0
 
     def set_correct_forces_algo(self, new_algo: int) -> int:
+        """Set the correction algorithm for forces."""
         assert new_algo in CORRALGO
         old_algo = self.__correct_forces_algo
         self.__correct_forces_algo = new_algo
@@ -994,16 +995,19 @@ def set_correct_forces_algo(self, new_algo: int) -> int:
 
     @property
     def correct_forces_algo(self) -> int:
+        """Correction algorithm for forces."""
         return self.__correct_forces_algo
 
     def set_correct_stress_algo(self, new_algo: int) -> int:
+        """Set the correction algorithm for the stress."""
         assert new_algo in CORRALGO
         old_algo = self.__correct_stress_algo
         self.__correct_stress_algo = new_algo
         return old_algo
 
     @property
-    def correct_stress_algo(self) -> bool:
+    def correct_stress_algo(self) -> int:
+        """Correction algorithm for the stress."""
         return self.__correct_stress_algo
 
     def store_abi_forstr_atoms(self, abi_forces, abi_stress, atoms):
@@ -1018,17 +1022,17 @@ def store_abi_forstr_atoms(self, abi_forces, abi_stress, atoms):
         self.__abi_stress_list.append(abi_stress)
         self.__abi_atoms_list.append(atoms.copy())
 
-        # Compute ML values 
+        # Compute ML forces ans stresses for the input atoms.
         self.reset()
         old_forces_algo = self.set_correct_forces_algo(CORRALGO.none)
         old_stress_algo = self.set_correct_stress_algo(CORRALGO.none)
         ml_forces = self.get_forces(atoms=atoms)
         ml_stress = self.get_stress(atoms=atoms)
         #print(f"{ml_forces=}"); print(f"{ml_stress=}")
-        self.set_correct_forces_algo(old_forces_algo)
-        self.set_correct_stress_algo(old_stress_algo)
         self.__ml_forces_list.append(ml_forces)
         self.__ml_stress_list.append(ml_stress)
+        self.set_correct_forces_algo(old_forces_algo)
+        self.set_correct_stress_algo(old_stress_algo)
         self.reset()
 
         def fmt_vec3(vec3) -> str:
@@ -1044,20 +1048,24 @@ def fmt_vec6(vec6) -> str:
                 print(f"abi_fcart_{iat=}:", fmt_vec3(abi_forces[iat]))
                 print(f"ml_fcart_{iat=} :", fmt_vec3(ml_forces[iat]))
 
-    def get_abi_forces(self):
-        if self.__abi_forces_list: return self.__abi_forces_list[-1]
+    def get_abi_forces(self, pos=-1):
+        """Return the ab-initio forces or None if not available."""
+        if self.__abi_forces_list: return self.__abi_forces_list[pos]
         return None
 
-    def get_ml_forces(self):
-        if self.__ml_forces_list: return self.__ml_forces_list[-1]
+    def get_ml_forces(self, pos=-1):
+        """Return the ML forces or None if not available."""
+        if self.__ml_forces_list: return self.__ml_forces_list[pos]
         return None
 
-    def get_abi_stress(self):
-        if self.__abi_stress_list: return self.__abi_stress_list[-1]
+    def get_abi_stress(self, pos=-1):
+        """Return the ab-initio stress or None if not available."""
+        if self.__abi_stress_list: return self.__abi_stress_list[pos]
         return None
 
-    def get_ml_stress(self):
-        if self.__ml_stress_list: return self.__ml_stress_list[-1]
+    def get_ml_stress(self, pos=-1):
+        """Return the ML stress or None if not available."""
+        if self.__ml_stress_list: return self.__ml_stress_list[pos]
         return None
 
     def calculate(
@@ -1080,7 +1088,7 @@ def calculate(
         super().calculate(atoms=atoms, properties=properties, system_changes=system_changes)
 
         if self.correct_forces_algo != CORRALGO.none:
-            # Apply ab-initio correction to ml_forces.
+            # Apply ab-initio correction to the ml_forces.
             forces = self.results["forces"]
             abi_forces = self.get_abi_forces()
             ml_forces = self.get_ml_forces()
@@ -1098,7 +1106,7 @@ def calculate(
                 self.results.update(forces=forces)
 
         if self.correct_stress_algo != CORRALGO.none:
-            # Apply ab-initio correction to stress.
+            # Apply ab-initio correction to the ml_stress.
             stress = self.results["stress"]
             abi_stress = self.get_abi_stress()
             ml_stress = self.get_ml_stress()