docs: def get(cls, session, record_id, endpoint_override=None):
          """Return a specific record.
  
          Args:
              session (requests.sessions.Session): Authenticated session.
              record_id (int): The ID of the record to get.
              endpoint_override (str, optional): Override the default
                  endpoint using this.
  
          Returns:
              helpscout.BaseModel: A record singleton, if existing. Otherwise
                  ``None``.
          """
          cls._check_implements('get')
          try:
              return cls(
                  endpoint_override or '/%s/%d.json' % (
                      cls.__endpoint__, record_id,
                  ),
                  singleton=True,
                  session=session,
              )
          except HelpScoutRemoteException as e:
              if e.status_code == 404:
                  return None
              else:
                  raise