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

     def _group_from_buffer(
         buff: AgentBuffer, cont_action_key: BufferKey, disc_action_key: BufferKey
     ) -> List["AgentAction"]:
+        """
+        Extracts continuous and discrete groupmate actions, as specified by BufferKey, and
+        returns a List of AgentActions that correspond to the groupmate's actions. List will
+        be of length equal to the maximum number of groupmates in the buffer. Any spots where
+        there are less agents than maximum, the actions will be padded with 0's.
+        """
         continuous_tensors: List[torch.Tensor] = []
         discrete_tensors: List[torch.Tensor] = []
         if cont_action_key in buff:
     @staticmethod
     def group_from_buffer(buff: AgentBuffer) -> List["AgentAction"]:
         """
-        A static method that accesses continuous and discrete action fields in an AgentBuffer
-        and constructs the corresponding AgentAction from the retrieved np arrays.
+        A static method that accesses next group continuous and discrete action fields in an AgentBuffer
+        and constructs a padded List of AgentActions that represent the group agent actions.
+        The List is of length equal to max number of groupmate agents in the buffer, and the AgentBuffer iss
+        of the same length as the buffer. Empty spots (e.g. when agents die) are padded with 0.
+        :param buff: AgentBuffer of a batch or trajectory
+        :return: List of groupmate's AgentActions
         """
         return AgentAction._group_from_buffer(
             buff, BufferKey.GROUP_CONTINUOUS_ACTION, BufferKey.GROUP_DISCRETE_ACTION
     def group_from_buffer_next(buff: AgentBuffer) -> List["AgentAction"]:
         """
-        A static method that accesses next continuous and discrete action fields in an AgentBuffer
-        and constructs the corresponding AgentAction from the retrieved np arrays.
+        A static method that accesses next group continuous and discrete action fields in an AgentBuffer
+        and constructs a padded List of AgentActions that represent the next group agent actions.
+        The List is of length equal to max number of groupmate agents in the buffer, and the AgentBuffer iss
+        of the same length as the buffer. Empty spots (e.g. when agents die) are padded with 0.
+        :param buff: AgentBuffer of a batch or trajectory
+        :return: List of groupmate's AgentActions
         """
         return AgentAction._group_from_buffer(
             buff, BufferKey.GROUP_NEXT_CONT_ACTION, BufferKey.GROUP_NEXT_DISC_ACTION
+        """
+        Flatten this AgentAction into a single torch Tensor of dimension (batch, num_continuous + num_one_hot_discrete).
+        Discrete actions are converted into one-hot and concatenated with continuous actions.
+        :param discrete_branches: List of sizes for discrete actions.
+        :return: Tensor of flattened actions.
+        """
         discrete_oh = ModelUtils.actions_to_onehot(
             self.discrete_tensor, discrete_branches
         )