old_contents: # Constant definitions
  
  CHECK_TYPES = (
      ('>', 'Greater than'),
      ('>=', 'Greater than or equal'),
      ('<', 'Less than'),
      ('<=', 'Less than or equal'),
      ('==', 'Equal to'),
  )
  
  PASSING_STATUS = 'PASSING'
  ACKED_STATUS = 'ACKED'
  WARNING_STATUS = 'WARNING'
  ERROR_STATUS = 'ERROR'
  CRITICAL_STATUS = 'CRITICAL'
  
  RAW_DATA_LIMIT = 500000
  
  DEFAULT_CHECK_FREQUENCY = 5
  DEFAULT_CHECK_RETRIES = 0
  
  DEFAULT_HTTP_TIMEOUT = 30
  MAX_HTTP_TIMEOUT = 32
  DEFAULT_HTTP_STATUS_CODE = 200
  
  DEFAULT_TCP_TIMEOUT = 8
  MAX_TCP_TIMEOUT = 16
  
  TIMESTAMP_FORMAT = "%b %d, %Y, %H:%M %Z"  # Eg: "Dec 10, 2018, 21:34 UTC"
  
  # options to present in the dropdown on the for creating an ack
  EXPIRE_AFTER_HOURS_OPTIONS = [1, 2, 4, 8, 24]
  
  # number of closed acks to show at the bottom of the acknowledgements page
  NUM_VISIBLE_CLOSED_ACKS = 12
  
  # when creating an ack, max seconds to wait for check to update before we just return the page + a warning message
  ACK_UPDATE_SERVICE_TIMEOUT_SECONDS = 5.0
  ACK_SERVICE_NOT_YET_UPDATED_MSG = "Check still running; there may be some delay until the " \
                                    "check and service have the 'acked' status."
  
new_contents: # Constant definitions
  
  CHECK_TYPES = (
      ('>', 'Greater than'),
      ('>=', 'Greater than or equal'),
      ('<', 'Less than'),
      ('<=', 'Less than or equal'),
      ('==', 'Equal to'),
  )
  
  PASSING_STATUS = 'PASSING'
  ACKED_STATUS = 'ACKED'
  WARNING_STATUS = 'WARNING'
  ERROR_STATUS = 'ERROR'
  CRITICAL_STATUS = 'CRITICAL'
  
  RAW_DATA_LIMIT = 500000
  
  DEFAULT_CHECK_FREQUENCY = 5
  DEFAULT_CHECK_RETRIES = 0
  
  DEFAULT_HTTP_TIMEOUT = 30
  MAX_HTTP_TIMEOUT = 32
  DEFAULT_HTTP_STATUS_CODE = 200
  
  DEFAULT_TCP_TIMEOUT = 8
  MAX_TCP_TIMEOUT = 16
  
  TIMESTAMP_FORMAT = "%b %d, %Y, %H:%M %Z"  # Eg: "Dec 10, 2018, 21:34 UTC"
  
  # options to present in the dropdown on the for creating an ack
  EXPIRE_AFTER_HOURS_OPTIONS = [1, 2, 4, 8, 12, 24, 48, 72]
  
  # number of closed acks to show at the bottom of the acknowledgements page
  NUM_VISIBLE_CLOSED_ACKS = 12
  
  # when creating an ack, max seconds to wait for check to update before we just return the page + a warning message
  ACK_UPDATE_SERVICE_TIMEOUT_SECONDS = 5.0
  ACK_SERVICE_NOT_YET_UPDATED_MSG = "Check still running; there may be some delay until the " \
                                    "check and service have the 'acked' status."
  
subject: Add 12h, 48h, and 72h hour expiration options for acks (#185)