class_docstr: T5 Agent.
  
  Relies on the T5 model implemented in huggingface
class_docstr_tok: ["T5","Agent",".","Relies","on","the","T5","model","implemented","in","huggingface"]
docstr: Override to include prefix, if necessary.
docstr_tok: ["Override","to","include","prefix",",","if","necessary","."]
code: def observe(self, observation):
      """
      Override to include prefix, if necessary.
      """
      if (
          self.opt["t5_generation_config"] is not None
          and "text" in observation
      ):
          config = TASK_CONFIGS[self.opt["t5_generation_config"]]
          try:
              observation.force_set(
                  "text", config["prefix"] + observation["text"]
              )
          except AttributeError:
              observation["text"] = (
                  config["prefix"] + observation["text"]
              )
  
      return super().observe(observation)
  
imports: import torch
  from typing import Optional, Dict, Any, Tuple
  from transformers import T5ForConditionalGeneration
  from parlai.agents.hugging_face.hugging_face import HF_VERSION
  from parlai.agents.hugging_face.dict import T5DictionaryAgent
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.core.torch_agent import Batch, TorchAgent
  from parlai.core.torch_generator_agent import TorchGeneratorAgent, TorchGeneratorModel
  from parlai.utils.fsdp import is_fsdp, delay_halving
label_desc: Use image node_id 5 for calling the T5Agent obj's underlying member method code with example usage: obj.observe(observation) and returns: super