text: # subject consts
  ALGO = 'algo'
  DISCRA = 'discra'
  DUFFUR = 'diffur'
  MATAN = 'matan'
  PE = 'pe'
  SP = 'sp'
  OS = 'os'
  BJD = 'bjd'
  HISTORY = 'history'
  ENG = 'eng'
  SUBTYPE = 'subtype'
  
  # pages consts
  MAIN_PAGE = 'main'
  TIMETABLE_PAGE = 'timetable'
  ADDITIONAL_PAGE = 'additional'
  
  # User attributes
  USER_ID = 'user_id'
  USER_NICK = 'user_nick'
  USERNAME = 'username'
  CHAT_ID = 'chat_id'
  ADMIN = 'admin'
  MUTED = 'muted'
  UTCOFFSET = 'utcoffset'
  LC = 'lc'
  
  # Persistence attributes
  CONVERSATIONS = 'conversations'
  
  # timetable consts
  WEEKDAY = 'weekday'
  MONDAY = 'monday'
  TUESDAY = 'tuesday'
  WEDNESDAY = 'wednesday'
  THURSDAY = 'thursday'
  FRIDAY = 'friday'
  SATURDAY = 'saturday'
  SUNDAY = 'sunday'
  TODAY = 'today'
  
  # handler types
  COMMAND = 'command'
  MESSAGE = 'message'
  
  # ConversationHandlers' states
  MAIN_STATE = 'main_state'
  PARAMETERS_STATE = 'parameters_state'
  ADMIN_STATE = 'admin_state'
  REPORT_STATE = 'report_state'
  REPORT_MESSAGE_STATE = 'report_message_state'
  ADMIN_NOTIFY_STATE = 'admin_notify_state'
  PARAMETERS_MAIN_STATE = 'parameters_main_state'
  PARAMETERS_TIME_STATE = 'parameters_time_state'
  PARAMETERS_TZINFO_STATE = 'parameters_tzinfo_state'
  PARAMETERS_NAME_STATE = 'parameters_name_state'
  
  # attendance consts
  ATTENDANCE = 'attendance'
  ATTENDANCE_BOTH = 'both'
  ATTENDANCE_ONLINE = 'online'
  ATTENDANCE_OFFLINE = 'offline'
  
  # week parity consts
  WEEK_PARITY = 'week_parity'
  WEEK_ODD = 'odd'
  WEEK_EVEN = 'even'
  WEEK_BOTH = 'both'
  
  # mailing consts
  MAILING_TIME = 'mailing_time'
  MAILING_STATUS = 'mailing_status'
  MAILING_ALLOWED = 'allowed'
  MAILING_FORBIDDEN = 'forbidden'
  NOTIFICATION_STATUS = 'notification_status'
  NOTIFICATION_ENABLED = 'enabled'
  NOTIFICATION_DISABLED = 'disabled'
  
  # mute consts
  MUTE = 'mute'
  UNMUTE = 'unmute'
  
  # jobs
  MAILING_JOB = 'mailing_job'
  
  # admin ls pages
  FIRST_PAGE = 'first'
  LAST_PAGE = 'last'
  MIDDLE_PAGE = 'middle'
  SINGLE_PAGE = 'single'
  PAGE_NUMBER = 'page_number'
  USERS = 'users'
  TOTAL = 'total'
  LB = 'lb'  # left bound
  RB = 'rb'  # right bound
  
  # deadlines consts
  DATE = 'date'
  DEADLINE = 'deadline'
  DAY_ID = 'day_id'
  DEADLINE_DAY_FORMAT = '%d/%m'
  
  # other
  DOC_COMMANDS = {'doc', 'help', 'parameters', 'today', 'timetable', 'report', 'admin'}
  ALL = 'all'
  DEV = 'dev'
  PROD = 'prod'
  UNKNOWN = 'unknown'
  TIMETABLE = 'timetable'
  SUBJECT = 'subject'
  PAGE = 'page'
  TEXT = 'text'
  COURSES = 'courses'
  ENTER_NAME = 'enter_name'
  ENTER_TIME = 'enter_time'
  ENTER_TZINFO = 'enter_tzinfo'
  HELP = 'help'
  CANCEL = 'cancel'
  MAILING = 'mailing'
  FOOTER = 'footer'
  QUOTE = 'quote'
  AUTHOR = 'author'
  