old_contents: import datetime
  import decimal
  
  from django.utils import timezone
  
  
  def convert_tstamp(response, field_name=None):
      try:
          if field_name and response[field_name]:
              return datetime.datetime.fromtimestamp(
                  response[field_name],
                  timezone.utc
              )
          if not field_name:
              return datetime.datetime.fromtimestamp(
                  response,
                  timezone.utc
              )
      except KeyError:
          pass
      return None
  
  
  # currencies those amount=1 means 100 cents
  # https://support.stripe.com/questions/which-zero-decimal-currencies-does-stripe-support
  ZERO_DECIMAL_CURRENCIES = [
      "bif", "clp", "djf", "gnf", "jpy", "kmf", "krw",
      "mga", "pyg", "rwf", "vuv", "xaf", "xof", "xpf",
  ]
  
  
  def convert_amount_for_db(amount, currency="usd"):
      if currency is None:  # @@@ not sure if this is right; find out what we should do when API returns null for currency
          currency = "usd"
      return (amount / decimal.Decimal("100")) if currency.lower() not in ZERO_DECIMAL_CURRENCIES else decimal.Decimal(amount)
  
  
  def convert_amount_for_api(amount, currency="usd"):
      if currency is None:
          currency = "usd"
      return int(amount * 100) if currency.lower() not in ZERO_DECIMAL_CURRENCIES else int(amount)
  
new_contents: import datetime
  import decimal
  
  from django.utils import timezone
  
  
  def convert_tstamp(response, field_name=None):
      try:
          if field_name and response[field_name]:
              return datetime.datetime.fromtimestamp(
                  response[field_name],
                  timezone.utc
              )
          if response is not None and not field_name:
              return datetime.datetime.fromtimestamp(
                  response,
                  timezone.utc
              )
      except KeyError:
          pass
      return None
  
  
  # currencies those amount=1 means 100 cents
  # https://support.stripe.com/questions/which-zero-decimal-currencies-does-stripe-support
  ZERO_DECIMAL_CURRENCIES = [
      "bif", "clp", "djf", "gnf", "jpy", "kmf", "krw",
      "mga", "pyg", "rwf", "vuv", "xaf", "xof", "xpf",
  ]
  
  
  def convert_amount_for_db(amount, currency="usd"):
      if currency is None:  # @@@ not sure if this is right; find out what we should do when API returns null for currency
          currency = "usd"
      return (amount / decimal.Decimal("100")) if currency.lower() not in ZERO_DECIMAL_CURRENCIES else decimal.Decimal(amount)
  
  
  def convert_amount_for_api(amount, currency="usd"):
      if currency is None:
          currency = "usd"
      return int(amount * 100) if currency.lower() not in ZERO_DECIMAL_CURRENCIES else int(amount)
  
subject: Handle case when response is None