code: def unix(value):
      
      if isinstance(value, (date, builtin_datetime)):
          pass
      elif value < 10000000000:
          value = unix2datetime(value)
      else:
          value = milli2datetime(value)
  
      return str(datetime2unix(value))
docs: Convert a date, or datetime to unix timestamp
      :param value:
      :return: