Adding a helper method for creating observation placeholder names and removed the _h and _c placeholders

com.unity.ml-agents/Runtime/Inference/BarracudaModelParamLoader.cs

                 if (sensor.GetObservationShape().Length == 3)
                 {
                     if (!tensorsNames.Contains(
-                        TensorNames.VisualObservationPlaceholderPrefix + visObsIndex))
+                        TensorNames.GetVisualObservationName(visObsIndex)))
                     {
                         failedModelChecks.Add(
                             "The model does not contain a Visual Observation Placeholder Input " +
                 if (sensor.GetObservationShape().Length == 2)
                 {
                     if (!tensorsNames.Contains(
-                        TensorNames.ObservationPlaceholderPrefix + sensorIndex))
+                        TensorNames.GetObservationName(sensorIndex)))
                     {
                         failedModelChecks.Add(
                             "The model does not contain an Observation Placeholder Input " +
                 if (sens.GetObservationShape().Length == 3)
                 {
 
-                    tensorTester[TensorNames.VisualObservationPlaceholderPrefix + visObsIndex] =
+                    tensorTester[TensorNames.GetVisualObservationName(visObsIndex)] =
-                    tensorTester[TensorNames.ObservationPlaceholderPrefix + sensorIndex] =
+                    tensorTester[TensorNames.GetObservationName(sensorIndex)] =
                         (bp, tensor, scs, i) => CheckRankTwoObsShape(tensor, sens);
                 }
             }

com.unity.ml-agents/Runtime/Inference/TensorGenerator.cs

                         // If the tensor is of rank 2, we use the index of the sensor
                         // to create the name
                         obsGen = new ObservationGenerator(allocator);
-                        obsGenName = TensorNames.ObservationPlaceholderPrefix + sensorIndex;
+                        obsGenName = TensorNames.GetObservationName(sensorIndex);
-                        obsGenName = TensorNames.VisualObservationPlaceholderPrefix + visIndex;
+                        obsGenName = TensorNames.GetVisualObservationName(visIndex);
                         visIndex++;
                         break;
                     default:

com.unity.ml-agents/Runtime/Inference/TensorNames.cs

         public const string SequenceLengthPlaceholder = "sequence_length";
         public const string VectorObservationPlaceholder = "vector_observation";
         public const string RecurrentInPlaceholder = "recurrent_in";
-        public const string recurrentInPlaceholderH = "recurrent_in_h";
-        public const string recurrentInPlaceholderC = "recurrent_in_c";
         public const string VisualObservationPlaceholderPrefix = "visual_observation_";
         public const string ObservationPlaceholderPrefix = "obs_";
         public const string PreviousActionPlaceholder = "prev_action";
         public const string ValueEstimateOutput = "value_estimate";
         public const string RecurrentOutput = "recurrent_out";
-        public const string recurrentOutputH = "recurrent_out_h";
-        public const string recurrentOutputC = "recurrent_out_c";
         public const string MemorySize = "memory_size";
         public const string VersionNumber = "version_number";
         public const string ContinuousActionOutputShape = "continuous_action_output_shape";
         public const string IsContinuousControlDeprecated = "is_continuous_control";
         public const string ActionOutputDeprecated = "action";
         public const string ActionOutputShapeDeprecated = "action_output_shape";
+
+        /// <summary>
+        /// Returns the name of the visual observation with a given index
+        /// </summary>
+        public static string GetVisualObservationName(int index)
+        {
+            return VisualObservationPlaceholderPrefix + index;
+        }
+
+        /// <summary>
+        /// Returns the name of the observation with a given index
+        /// </summary>
+        public static string GetObservationName(int index)
+        {
+            return ObservationPlaceholderPrefix + index;
+        }
     }
 }

ml-agents/mlagents/trainers/torch/model_serialization.py

     sequence_length_placeholder = "sequence_length"
     vector_observation_placeholder = "vector_observation"
     recurrent_in_placeholder = "recurrent_in"
-    recurrent_in_placeholder_h = "recurrent_in_h"
-    recurrent_in_placeholder_c = "recurrent_in_c"
     visual_observation_placeholder_prefix = "visual_observation_"
     observation_placeholder_prefix = "obs_"
     previous_action_placeholder = "prev_action"
     value_estimate_output = "value_estimate"
     recurrent_output = "recurrent_out"
-    recurrent_output_h = "recurrent_out_h"
-    recurrent_output_c = "recurrent_out_c"
     memory_size = "memory_size"
     version_number = "version_number"
     continuous_action_output_shape = "continuous_action_output_shape"
     is_continuous_control_deprecated = "is_continuous_control"
     action_output_deprecated = "action"
     action_output_shape_deprecated = "action_output_shape"
+
+    @staticmethod
+    def get_visual_observation_name(index: int) -> str:
+        """
+        Returns the name of the visual observation with a given index
+        """
+        return TensorNames.visual_observation_placeholder_prefix + str(index)
+
+    @staticmethod
+    def get_observation_name(index: int) -> str:
+        """
+        Returns the name of the observation with a given index
+        """
+        return TensorNames.observation_placeholder_prefix + str(index)
 
 
 class ModelSerializer:
 
         self.input_names = [TensorNames.vector_observation_placeholder]
         for i in range(num_vis_obs):
-            self.input_names.append(
-                TensorNames.visual_observation_placeholder_prefix + str(i)
-            )
+            self.input_names.append(TensorNames.get_visual_observation_name(i))
-                self.input_names.append(
-                    TensorNames.observation_placeholder_prefix + str(i)
-                )
+                self.input_names.append(TensorNames.get_observation_name(i))
         self.input_names += [
             TensorNames.action_mask_placeholder,
             TensorNames.recurrent_in_placeholder,