docstr: From RobertaForSpanComparisonClassification
code: def __init__(self, task, hidden_size, hidden_dropout_prob, **kwargs):
      """From RobertaForSpanComparisonClassification"""
      super().__init__()
      self.num_spans = task.num_spans
      self.num_labels = len(task.LABELS)
      self.hidden_size = hidden_size
      self.dropout = nn.Dropout(hidden_dropout_prob)
      self.span_attention_extractor = SelfAttentiveSpanExtractor(
          hidden_size
      )
      self.classifier = nn.Linear(
          hidden_size * self.num_spans, self.num_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 SpanComparisonHead object from inherited base classes: BaseHead with example: obj = SpanComparisonHead(task, hidden_size, hidden_dropout_prob)