code: def create_file_header(self, f):
      commit_dates = retrieve_commit_dates(f)
      if len(commit_dates) == 0:
          return None
  
      sony_years = set()
      sony_group_years = set()
      for date in commit_dates:
          (year, month, _) = date.split("-")
          if int(year) <= 2020:
              sony_years.add(year)
          elif int(year) <= 2021 and int(month) < 4:
              sony_years.add(year)
          else:
              sony_group_years.add(year)
  
      header = ""
      if len(sony_years) != 0:
          sony_years = list(sony_years)
          sony_years = fill_intermediate_years(
              sony_years, end_year=2021
          )
          joined_sony_years = ",".join(sony_years)
          header += (
              self.copyright_sony_corp.format(joined_sony_years) + "\n"
          )
  
      if len(sony_group_years) != 0:
          sony_group_years = list(sony_group_years)
          sony_group_years = fill_intermediate_years(sony_group_years)
          joined_sony_group_years = ",".join(sony_group_years)
          header += (
              self.copyright_sony_group_corp.format(
                  joined_sony_group_years
              )
              + "\n"
          )
  
      header += self.apache2_license_template
  
      return header
  
imports: import argparse
  import os
  import pathlib
  import re
  import subprocess
  from tqdm import tqdm
  from contextlib import contextmanager
label_desc: Use image node_id 6 for calling the Checker obj's underlying member method code with example usage: obj.create_file_header(f) and returns: header, None