docstr: From RobertaClassificationHead
code: def __init__(self, task, hidden_size, hidden_dropout_prob, **kwargs):
      """From RobertaClassificationHead"""
      super().__init__()
      self.dense = nn.Linear(hidden_size, hidden_size)
      self.dropout = nn.Dropout(hidden_dropout_prob)
      self.out_proj = nn.Linear(hidden_size, len(task.LABELS))
      self.num_labels = len(task.LABELS)
  
imports: from __future__ import annotations
  import abc
  import torch
  import torch.nn
  import transformers
  from jiant.ext.allennlp import SelfAttentiveSpanExtractor
  from jiant.shared.model_resolution import ModelArchitectures
  from jiant.tasks.core import TaskTypes
  from typing import Callable
  from typing import List
label_desc: Use image node_id 1 to create a new ClassificationHead object from inherited base classes: BaseHead with example: obj = ClassificationHead(task, hidden_size, hidden_dropout_prob)