docs: def vt_hash_check(fhash, vt_api):
      """Checks VirusTotal for occurrences of a file hash"""
      if not is_hash(fhash):
          return None
  
      url = 'https://www.virustotal.com/vtapi/v2/file/report'
      parameters = {'resource': fhash, 'apikey': vt_api}
      response = requests.get(url, params=parameters)
      try:
          return response.json()
      except ValueError:
          return None