old_contents: from datetime import datetime, time, timezone
  
  
  def time_min():
      return time.min.replace(tzinfo=timezone.utc)
  
  
  def time_max():
      return time.max.replace(tzinfo=timezone.utc)
  
  
  def datetime_min():
      return datetime.min.replace(tzinfo=timezone.utc)
  
  
  def datetime_max():
      return datetime.max.replace(tzinfo=timezone.utc)
  
new_contents: from typing import NewType
  from datetime import datetime, time, timezone, date
  
  
  TimeTz = NewType('TimeTz', time)
  DateTimeTz = NewType('DateTimeTz', datetime)
  DateTimeNoTz = NewType('DateTimeNoTz', datetime)
  
  
  def time_min() -> TimeTz:
      return time.min.replace(tzinfo=timezone.utc)
  
  
  def time_max() -> TimeTz:
      return time.max.replace(tzinfo=timezone.utc)
  
  
  def datetime_min() -> DateTimeTz:
      return datetime.min.replace(tzinfo=timezone.utc)
  
  
  def datetime_max() -> DateTimeTz:
      return datetime.max.replace(tzinfo=timezone.utc)
  
subject: Introduce static types like `DateTimeTz` and annotate `utc` helpers