Module aws_lambda_powertools.utilities.feature_flags.schema
Classes
class ConditionsValidator (rule: dict[str, Any], rule_name: str, logger: logging.Logger | Logger | None = None)
-
Helper class that provides a standard way to create an ABC using inheritance.
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class ConditionsValidator(BaseValidator): def __init__(self, rule: dict[str, Any], rule_name: str, logger: logging.Logger | Logger | None = None): self.conditions: list[dict[str, Any]] = rule.get(CONDITIONS_KEY, {}) self.rule_name = rule_name self.logger = logger or LOGGER def validate(self): if not self.conditions or not isinstance(self.conditions, list): self.logger.debug(f"Condition is empty or invalid for rule={self.rule_name}") raise SchemaValidationError(f"Invalid condition, rule={self.rule_name}") for condition in self.conditions: # Condition can contain PII data; do not log condition value self.logger.debug(f"Attempting to validate condition for {self.rule_name}") self.validate_condition(rule_name=self.rule_name, condition=condition) @staticmethod def validate_condition(rule_name: str, condition: dict[str, str]) -> None: if not condition or not isinstance(condition, dict): raise SchemaValidationError(f"Feature rule condition must be a dictionary, rule={rule_name}") ConditionsValidator.validate_condition_action(condition=condition, rule_name=rule_name) ConditionsValidator.validate_condition_key(condition=condition, rule_name=rule_name) ConditionsValidator.validate_condition_value(condition=condition, rule_name=rule_name) @staticmethod def validate_condition_action(condition: dict[str, Any], rule_name: str): action = condition.get(CONDITION_ACTION, "") if action not in RuleAction.__members__: allowed_values = [_action.value for _action in RuleAction] raise SchemaValidationError( f"'action' value must be either {allowed_values}, rule_name={rule_name}, action={action}", ) @staticmethod def validate_condition_key(condition: dict[str, Any], rule_name: str): key = condition.get(CONDITION_KEY, "") if not key or not isinstance(key, str): raise SchemaValidationError(f"'key' value must be a non empty string, rule={rule_name}") action = condition.get(CONDITION_ACTION, "") # To allow for growth and prevent if/elif chains, we align extra validators based on the action name. # for example: # # SCHEDULE_BETWEEN_DAYS_OF_WEEK_KEY # - extra validation: `_validate_schedule_between_days_of_week_key` # # maintenance: we should split to separate file/classes for better organization, e.g., visitor pattern. custom_validator = getattr(ConditionsValidator, f"_validate_{action.lower()}_key", None) # ~90% of actions available don't require a custom validator # logging a debug statement for no-match will increase CPU cycles for most customers # for that reason only, we invert and log only when extra validation is found. if custom_validator is None: return LOGGER.debug(f"{action} requires key validation. Running '{custom_validator}' validator.") custom_validator(key, rule_name) @staticmethod def validate_condition_value(condition: dict[str, Any], rule_name: str): value = condition.get(CONDITION_VALUE) if value is None: raise SchemaValidationError(f"'value' key must not be null, rule={rule_name}") action = condition.get(CONDITION_ACTION, "") # To allow for growth and prevent if/elif chains, we align extra validators based on the action name. # for example: # # SCHEDULE_BETWEEN_DAYS_OF_WEEK_KEY # - extra validation: `_validate_schedule_between_days_of_week_value` # # maintenance: we should split to separate file/classes for better organization, e.g., visitor pattern. custom_validator = getattr(ConditionsValidator, f"_validate_{action.lower()}_value", None) # ~90% of actions available don't require a custom validator # logging a debug statement for no-match will increase CPU cycles for most customers # for that reason only, we invert and log only when extra validation is found. if custom_validator is None: return LOGGER.debug(f"{action} requires value validation. Running '{custom_validator}' validator.") custom_validator(value, rule_name) @staticmethod def _validate_schedule_between_days_of_week_key(key: str, rule_name: str): if key != TimeKeys.CURRENT_DAY_OF_WEEK.value: raise SchemaValidationError( f"'condition with a 'SCHEDULE_BETWEEN_DAYS_OF_WEEK' action must have a 'CURRENT_DAY_OF_WEEK' condition key, rule={rule_name}", # noqa: E501 ) @staticmethod def _validate_schedule_between_days_of_week_value(value: dict, rule_name: str): error_str = f"condition with a CURRENT_DAY_OF_WEEK action must have a condition value dictionary with 'DAYS' and 'TIMEZONE' (optional) keys, rule={rule_name}" # noqa: E501 if not isinstance(value, dict): raise SchemaValidationError(error_str) days = value.get(TimeValues.DAYS.value) if not isinstance(days, list) or not value: raise SchemaValidationError(error_str) valid_days = TimeValues.days() for day in days: if not isinstance(day, str) or day not in valid_days: raise SchemaValidationError( f"condition value DAYS must represent a day of the week in 'TimeValues' enum, rule={rule_name}", ) ConditionsValidator._validate_timezone(timezone=value.get(TimeValues.TIMEZONE.value), rule=rule_name) @staticmethod def _validate_schedule_between_time_range_key(key: str, rule_name: str): if key != TimeKeys.CURRENT_TIME.value: raise SchemaValidationError( f"'condition with a 'SCHEDULE_BETWEEN_TIME_RANGE' action must have a 'CURRENT_TIME' condition key, rule={rule_name}", # noqa: E501 ) @staticmethod def _validate_schedule_between_time_range_value(value: dict, rule_name: str): if not isinstance(value, dict): raise SchemaValidationError( f"{RuleAction.SCHEDULE_BETWEEN_TIME_RANGE.value} action must have a dictionary with 'START' and 'END' keys, rule={rule_name}", # noqa: E501 ) start_time = value.get(TimeValues.START.value, "") end_time = value.get(TimeValues.END.value, "") if not isinstance(start_time, str) or not isinstance(end_time, str): raise SchemaValidationError(f"'START' and 'END' must be a non empty string, rule={rule_name}") # Using a regex instead of strptime because it's several orders of magnitude faster if not TIME_RANGE_PATTERN.match(start_time) or not TIME_RANGE_PATTERN.match(end_time): raise SchemaValidationError( f"'START' and 'END' must be a valid time format, time_format={TIME_RANGE_FORMAT}, rule={rule_name}", ) ConditionsValidator._validate_timezone(timezone=value.get(TimeValues.TIMEZONE.value), rule=rule_name) @staticmethod def _validate_schedule_between_datetime_range_key(key: str, rule_name: str): if key != TimeKeys.CURRENT_DATETIME.value: raise SchemaValidationError( f"'condition with a 'SCHEDULE_BETWEEN_DATETIME_RANGE' action must have a 'CURRENT_DATETIME' condition key, rule={rule_name}", # noqa: E501 ) @staticmethod def _validate_schedule_between_datetime_range_value(value: dict, rule_name: str): if not isinstance(value, dict): raise SchemaValidationError( f"{RuleAction.SCHEDULE_BETWEEN_DATETIME_RANGE.value} action must have a dictionary with 'START' and 'END' keys, rule={rule_name}", # noqa: E501 ) start_time = value.get(TimeValues.START.value, "") end_time = value.get(TimeValues.END.value, "") if not isinstance(start_time, str) or not isinstance(end_time, str): raise SchemaValidationError(f"'START' and 'END' must be a non empty string, rule={rule_name}") ConditionsValidator._validate_datetime(start_time, rule_name) ConditionsValidator._validate_datetime(end_time, rule_name) ConditionsValidator._validate_timezone(timezone=value.get(TimeValues.TIMEZONE.value), rule=rule_name) @staticmethod def _validate_modulo_range_value(value: dict, rule_name: str): error_str = f"condition with a 'MODULO_RANGE' action must have a condition value type dictionary with 'BASE', 'START' and 'END' keys, rule={rule_name}" # noqa: E501 if not isinstance(value, dict): raise SchemaValidationError(error_str) base = value.get(ModuloRangeValues.BASE.value) start = value.get(ModuloRangeValues.START.value) end = value.get(ModuloRangeValues.END.value) if base is None or start is None or end is None: raise SchemaValidationError(error_str) if not isinstance(base, int) or not isinstance(start, int) or not isinstance(end, int): raise SchemaValidationError(f"'BASE', 'START' and 'END' must be integers, rule={rule_name}") if not 0 <= start <= end <= base - 1: raise SchemaValidationError( f"condition with 'MODULO_RANGE' action must satisfy 0 <= START <= END <= BASE-1, rule={rule_name}", ) @staticmethod def _validate_all_in_value_value(value: list, rule_name: str): if not (isinstance(value, list)): raise SchemaValidationError(f"ALL_IN_VALUE action must have a list value, rule={rule_name}") @staticmethod def _validate_any_in_value_value(value: list, rule_name: str): if not (isinstance(value, list)): raise SchemaValidationError(f"ANY_IN_VALUE action must have a list value, rule={rule_name}") @staticmethod def _validate_none_in_value_value(value: list, rule_name: str): if not (isinstance(value, list)): raise SchemaValidationError(f"NONE_IN_VALUE action must have a list value, rule={rule_name}") @staticmethod def _validate_datetime(datetime_str: str, rule_name: str): date = None # We try to parse first with timezone information in order to return the correct error messages # when a timestamp with timezone is used. Otherwise, the user would get the first error "must be a valid # ISO8601 time format" which is misleading try: # python < 3.11 don't support the Z timezone on datetime.fromisoformat, # so we replace any Z with the equivalent "+00:00" # datetime.fromisoformat is orders of magnitude faster than datetime.strptime date = datetime.fromisoformat(datetime_str.replace("Z", "+00:00")) except Exception: raise SchemaValidationError(f"'START' and 'END' must be a valid ISO8601 time format, rule={rule_name}") # we only allow timezone information to be set via the TIMEZONE field # this way we can encode DST into the calculation. For instance, Copenhagen is # UTC+2 during winter, and UTC+1 during summer, which would be impossible to define # using a single ISO datetime string if date.tzinfo is not None: raise SchemaValidationError( "'START' and 'END' must not include timezone information. Set the timezone using the 'TIMEZONE' " f"field, rule={rule_name} ", ) @staticmethod def _validate_timezone(rule: str, timezone: str | None = None): timezone = timezone or "UTC" if not isinstance(timezone, str): raise SchemaValidationError(f"'TIMEZONE' must be a string, rule={str}") # try to see if the timezone string corresponds to any known timezone if not tz.gettz(timezone): raise SchemaValidationError(f"'TIMEZONE' value must represent a valid IANA timezone, rule={rule}")
Ancestors
- BaseValidator
- abc.ABC
Static methods
def validate_condition(rule_name: str, condition: dict[str, str]) ‑> None
def validate_condition_action(condition: dict[str, Any], rule_name: str)
def validate_condition_key(condition: dict[str, Any], rule_name: str)
def validate_condition_value(condition: dict[str, Any], rule_name: str)
Methods
def validate(self)
class FeaturesValidator (schema: dict, logger: logging.Logger | Logger | None = None)
-
Validates each feature and calls RulesValidator to validate its rules
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class FeaturesValidator(BaseValidator): """Validates each feature and calls RulesValidator to validate its rules""" def __init__(self, schema: dict, logger: logging.Logger | Logger | None = None): self.schema = schema self.logger = logger or LOGGER def validate(self): for name, feature in self.schema.items(): self.logger.debug(f"Attempting to validate feature '{name}'") boolean_feature: bool = self.validate_feature(name, feature) rules = RulesValidator(feature=feature, boolean_feature=boolean_feature, logger=self.logger) rules.validate() # returns True in case the feature is a regular feature flag with a boolean default value @staticmethod def validate_feature(name, feature) -> bool: if not feature or not isinstance(feature, dict): raise SchemaValidationError(f"Feature must be a non-empty dictionary, feature={name}") default_value: Any = feature.get(FEATURE_DEFAULT_VAL_KEY) boolean_feature: bool = feature.get(FEATURE_DEFAULT_VAL_TYPE_KEY, True) # if feature is boolean_feature, default_value must be a boolean type. # default_value must exist # Maintenance: Revisit before going GA. We might to simplify customers on-boarding by not requiring it # for non-boolean flags. if default_value is None or (not isinstance(default_value, bool) and boolean_feature): raise SchemaValidationError(f"feature 'default' boolean key must be present, feature={name}") return boolean_feature
Ancestors
- BaseValidator
- abc.ABC
Static methods
def validate_feature(name, feature) ‑> bool
Methods
def validate(self)
class ModuloRangeValues (*args, **kwds)
-
Possible values when using modulo range rule
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class ModuloRangeValues(Enum): """ Possible values when using modulo range rule """ BASE = "BASE" START = "START" END = "END"
Ancestors
- enum.Enum
Class variables
var BASE
var END
var START
class RuleAction (*args, **kwds)
-
str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str
Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to sys.getdefaultencoding(). errors defaults to 'strict'.
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class RuleAction(str, Enum): EQUALS = "EQUALS" NOT_EQUALS = "NOT_EQUALS" KEY_GREATER_THAN_VALUE = "KEY_GREATER_THAN_VALUE" KEY_GREATER_THAN_OR_EQUAL_VALUE = "KEY_GREATER_THAN_OR_EQUAL_VALUE" KEY_LESS_THAN_VALUE = "KEY_LESS_THAN_VALUE" KEY_LESS_THAN_OR_EQUAL_VALUE = "KEY_LESS_THAN_OR_EQUAL_VALUE" STARTSWITH = "STARTSWITH" ENDSWITH = "ENDSWITH" IN = "IN" NOT_IN = "NOT_IN" KEY_IN_VALUE = "KEY_IN_VALUE" KEY_NOT_IN_VALUE = "KEY_NOT_IN_VALUE" VALUE_IN_KEY = "VALUE_IN_KEY" VALUE_NOT_IN_KEY = "VALUE_NOT_IN_KEY" ALL_IN_VALUE = "ALL_IN_VALUE" ANY_IN_VALUE = "ANY_IN_VALUE" NONE_IN_VALUE = "NONE_IN_VALUE" SCHEDULE_BETWEEN_TIME_RANGE = "SCHEDULE_BETWEEN_TIME_RANGE" # hour:min 24 hours clock SCHEDULE_BETWEEN_DATETIME_RANGE = "SCHEDULE_BETWEEN_DATETIME_RANGE" # full datetime format, excluding timezone SCHEDULE_BETWEEN_DAYS_OF_WEEK = "SCHEDULE_BETWEEN_DAYS_OF_WEEK" # MONDAY, TUESDAY, .... see TimeValues enum MODULO_RANGE = "MODULO_RANGE"
Ancestors
- builtins.str
- enum.Enum
Class variables
var ALL_IN_VALUE
var ANY_IN_VALUE
var ENDSWITH
var EQUALS
var IN
var KEY_GREATER_THAN_OR_EQUAL_VALUE
var KEY_GREATER_THAN_VALUE
var KEY_IN_VALUE
var KEY_LESS_THAN_OR_EQUAL_VALUE
var KEY_LESS_THAN_VALUE
var KEY_NOT_IN_VALUE
var MODULO_RANGE
var NONE_IN_VALUE
var NOT_EQUALS
var NOT_IN
var SCHEDULE_BETWEEN_DATETIME_RANGE
var SCHEDULE_BETWEEN_DAYS_OF_WEEK
var SCHEDULE_BETWEEN_TIME_RANGE
var STARTSWITH
var VALUE_IN_KEY
var VALUE_NOT_IN_KEY
class RulesValidator (feature: dict[str, Any], boolean_feature: bool, logger: logging.Logger | Logger | None = None)
-
Validates each rule and calls ConditionsValidator to validate each rule's conditions
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class RulesValidator(BaseValidator): """Validates each rule and calls ConditionsValidator to validate each rule's conditions""" def __init__( self, feature: dict[str, Any], boolean_feature: bool, logger: logging.Logger | Logger | None = None, ): self.feature = feature self.feature_name = next(iter(self.feature)) self.rules: dict | None = self.feature.get(RULES_KEY) self.logger = logger or LOGGER self.boolean_feature = boolean_feature def validate(self): if not self.rules: self.logger.debug("Rules are empty, ignoring validation") return if not isinstance(self.rules, dict): self.logger.debug(f"Feature rules must be a dictionary, feature={self.feature_name}") raise SchemaValidationError(f"Feature rules must be a dictionary, feature={self.feature_name}") for rule_name, rule in self.rules.items(): self.logger.debug(f"Attempting to validate rule={rule_name} and feature={self.feature_name}") self.validate_rule( rule=rule, rule_name=rule_name, feature_name=self.feature_name, boolean_feature=self.boolean_feature, ) conditions = ConditionsValidator(rule=rule, rule_name=rule_name, logger=self.logger) conditions.validate() @staticmethod def validate_rule(rule: dict, rule_name: str, feature_name: str, boolean_feature: bool = True): if not rule or not isinstance(rule, dict): raise SchemaValidationError(f"Feature rule must be a dictionary, feature={feature_name}") RulesValidator.validate_rule_name(rule_name=rule_name, feature_name=feature_name) RulesValidator.validate_rule_default_value(rule=rule, rule_name=rule_name, boolean_feature=boolean_feature) @staticmethod def validate_rule_name(rule_name: str, feature_name: str): if not rule_name or not isinstance(rule_name, str): raise SchemaValidationError(f"Rule name key must have a non-empty string, feature={feature_name}") @staticmethod def validate_rule_default_value(rule: dict, rule_name: str, boolean_feature: bool): rule_default_value = rule.get(RULE_MATCH_VALUE) if boolean_feature and not isinstance(rule_default_value, bool): raise SchemaValidationError(f"'rule_default_value' key must have be bool, rule={rule_name}")
Ancestors
- BaseValidator
- abc.ABC
Static methods
def validate_rule(rule: dict, rule_name: str, feature_name: str, boolean_feature: bool = True)
def validate_rule_default_value(rule: dict, rule_name: str, boolean_feature: bool)
def validate_rule_name(rule_name: str, feature_name: str)
Methods
def validate(self)
class SchemaValidator (schema: dict[str, Any], logger: logging.Logger | Logger | None = None)
-
Validates feature flag schema configuration
Raises
SchemaValidationError
- When schema doesn't conform with feature flag schema
Schema
Feature object
A dictionary containing default value and rules for matching. The value MUST be an object and MIGHT contain the following members:
- default:
bool | JSONType
. Defines default feature value. This MUST be present - boolean_type: bool. Defines whether feature has non-boolean value (
JSONType
). This MIGHT be present - rules:
dict[str, dict]
. Rules object. This MIGHT be present
JSONType
being any JSON primitive value:str | int | float | bool | None | dict[str, Any] | list[Any]
{ "my_feature": { "default": true, "rules": {} }, "my_non_boolean_feature": { "default": {"group": "read-only"}, "boolean_type": false, "rules": {} } }
Rules object
A dictionary with each rule and their conditions that a feature might have. The value MIGHT be present, and when defined it MUST contain the following members:
- when_match:
bool | JSONType
. Defines value to return when context matches conditions - conditions:
list[dict]
. Conditions object. This MUST be present
{ "my_feature": { "default": true, "rules": { "tenant id equals 345345435": { "when_match": false, "conditions": [] } } }, "my_non_boolean_feature": { "default": {"group": "read-only"}, "boolean_type": false, "rules": { "tenant id equals 345345435": { "when_match": {"group": "admin"}, "conditions": [] } } } }
Conditions object
A list of dictionaries containing conditions for a given rule. The value MUST contain the following members:
-
action:
str
. Operation to perform to match a key and value. The value MUST be either EQUALS, STARTSWITH, ENDSWITH, KEY_IN_VALUE KEY_NOT_IN_VALUE VALUE_IN_KEY VALUE_NOT_IN_KEY -
key:
str
. Key in given context to perform operation - value:
Any
. Value in given context that should match action operation.
{ "my_feature": { "default": true, "rules": { "tenant id equals 345345435": { "when_match": false, "conditions": [ { "action": "EQUALS", "key": "tenant_id", "value": "345345435", } ] } } } }
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class SchemaValidator(BaseValidator): """Validates feature flag schema configuration Raises ------ SchemaValidationError When schema doesn't conform with feature flag schema Schema ------ **Feature object** A dictionary containing default value and rules for matching. The value MUST be an object and MIGHT contain the following members: * **default**: `bool | JSONType`. Defines default feature value. This MUST be present * **boolean_type**: bool. Defines whether feature has non-boolean value (`JSONType`). This MIGHT be present * **rules**: `dict[str, dict]`. Rules object. This MIGHT be present `JSONType` being any JSON primitive value: `str | int | float | bool | None | dict[str, Any] | list[Any]` ```json { "my_feature": { "default": true, "rules": {} }, "my_non_boolean_feature": { "default": {"group": "read-only"}, "boolean_type": false, "rules": {} } } ``` **Rules object** A dictionary with each rule and their conditions that a feature might have. The value MIGHT be present, and when defined it MUST contain the following members: * **when_match**: `bool | JSONType`. Defines value to return when context matches conditions * **conditions**: `list[dict]`. Conditions object. This MUST be present ```json { "my_feature": { "default": true, "rules": { "tenant id equals 345345435": { "when_match": false, "conditions": [] } } }, "my_non_boolean_feature": { "default": {"group": "read-only"}, "boolean_type": false, "rules": { "tenant id equals 345345435": { "when_match": {"group": "admin"}, "conditions": [] } } } } ``` **Conditions object** A list of dictionaries containing conditions for a given rule. The value MUST contain the following members: * **action**: `str`. Operation to perform to match a key and value. The value MUST be either EQUALS, STARTSWITH, ENDSWITH, KEY_IN_VALUE KEY_NOT_IN_VALUE VALUE_IN_KEY VALUE_NOT_IN_KEY * **key**: `str`. Key in given context to perform operation * **value**: `Any`. Value in given context that should match action operation. ```json { "my_feature": { "default": true, "rules": { "tenant id equals 345345435": { "when_match": false, "conditions": [ { "action": "EQUALS", "key": "tenant_id", "value": "345345435", } ] } } } } ``` """ def __init__(self, schema: dict[str, Any], logger: logging.Logger | Logger | None = None): self.schema = schema self.logger = logger or LOGGER # Validators are designed for modular testing # therefore we link the custom logger with global LOGGER # so custom validators can use them when necessary SchemaValidator._link_global_logger(self.logger) def validate(self) -> None: self.logger.debug("Validating schema") if not isinstance(self.schema, dict): raise SchemaValidationError(f"Features must be a dictionary, schema={str(self.schema)}") features = FeaturesValidator(schema=self.schema, logger=self.logger) features.validate() @staticmethod def _link_global_logger(logger: logging.Logger | Logger): global LOGGER LOGGER = logger
Ancestors
- BaseValidator
- abc.ABC
Methods
def validate(self) ‑> None
class TimeKeys (*args, **kwds)
-
Possible keys when using time rules
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class TimeKeys(Enum): """ Possible keys when using time rules """ CURRENT_TIME = "CURRENT_TIME" CURRENT_DAY_OF_WEEK = "CURRENT_DAY_OF_WEEK" CURRENT_DATETIME = "CURRENT_DATETIME"
Ancestors
- enum.Enum
Class variables
var CURRENT_DATETIME
var CURRENT_DAY_OF_WEEK
var CURRENT_TIME
class TimeValues (*args, **kwds)
-
Possible values when using time rules
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class TimeValues(Enum): """ Possible values when using time rules """ START = "START" END = "END" TIMEZONE = "TIMEZONE" DAYS = "DAYS" SUNDAY = "SUNDAY" MONDAY = "MONDAY" TUESDAY = "TUESDAY" WEDNESDAY = "WEDNESDAY" THURSDAY = "THURSDAY" FRIDAY = "FRIDAY" SATURDAY = "SATURDAY" @classmethod @lru_cache(maxsize=1) def days(cls) -> list[str]: return [day.value for day in cls if day.value not in ["START", "END", "TIMEZONE"]]
Ancestors
- enum.Enum
Class variables
var DAYS
var END
var FRIDAY
var MONDAY
var SATURDAY
var START
var SUNDAY
var THURSDAY
var TIMEZONE
var TUESDAY
var WEDNESDAY
Static methods
def days(cls) ‑> list[str]