class_docstr: FVQA Teacher, which loads the json VQA data and implements its own `act` method for
  interacting with student agent.
  
  Use "fvqa:split:X" to choose between splits 0-4 (inclusive), or just "fvqa" to use
  the default split (0).
docstr: Process observation for metrics.
docstr_tok: ["Process","observation","for","metrics","."]
code: def observe(self, observation):
      """
      Process observation for metrics.
      """
      if self.lastY is not None:
          if self.asked_question:
              self.metrics.evaluate_response(observation, self.lastY[0])
          else:
              self.factmetrics.evaluate_response(
                  observation, self.lastY[1]
              )
              self.lastY = None
      return observation
  
imports: from parlai.core.image_featurizers import ImageLoader
  from parlai.core.metrics import TeacherMetrics
  from parlai.core.teachers import Teacher
  from parlai.utils.io import PathManager
  from .build import build
  import json
  import random
  import os
label_desc: Use image node_id 7 for calling the SplitTeacher obj's underlying member method code with example usage: obj.observe(observation) and returns: observation