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enum — Support for enumerations¶New in version 3.4.
Source code: Lib/enum.py
An enumeration is a set of symbolic names (members) bound to unique, constant values. Within an enumeration, the members can be compared by identity, and the enumeration itself can be iterated over.
This module defines four enumeration classes that can be used to define unique
sets of names and values: Enum, IntEnum, Flag, and
IntFlag. It also defines one decorator, unique(), and one
helper, auto.
enum.Enum¶Base class for creating enumerated constants. See section Functional API for an alternate construction syntax.
enum.IntFlag¶Base class for creating enumerated constants that can be combined using
the bitwise operators without losing their IntFlag membership.
IntFlag members are also subclasses of int.
enum.Flag¶Base class for creating enumerated constants that can be combined using
the bitwise operations without losing their Flag membership.
enum.unique()¶Enum class decorator that ensures only one name is bound to any one value.
enum.auto¶Instances are replaced with an appropriate value for Enum members.
New in version 3.6: Flag, IntFlag, auto
Enumerations are created using the class syntax, which makes them
easy to read and write. An alternative creation method is described in
Functional API. To define an enumeration, subclass Enum as
follows:
>>> from enum import Enum
>>> class Color(Enum):
... RED = 1
... GREEN = 2
... BLUE = 3
...
Note
Enum member values
Member values can be anything: int, str, etc.. If
the exact value is unimportant you may use auto instances and an
appropriate value will be chosen for you. Care must be taken if you mix
auto with other values.
Note
Nomenclature
Color is an enumeration (or enum)Color.RED, Color.GREEN, etc., are
enumeration members (or enum members) and are functionally constants.Color.RED is RED, the value of Color.BLUE is
3, etc.)Note
Even though we use the class syntax to create Enums, Enums
are not normal Python classes. See How are Enums different? for
more details.
Enumeration members have human readable string representations:
>>> print(Color.RED)
Color.RED
...while their repr has more information:
>>> print(repr(Color.RED))
<Color.RED: 1>
The type of an enumeration member is the enumeration it belongs to:
>>> type(Color.RED)
<enum 'Color'>
>>> isinstance(Color.GREEN, Color)
True
>>>
Enum members also have a property that contains just their item name:
>>> print(Color.RED.name)
RED
Enumerations support iteration, in definition order:
>>> class Shake(Enum):
... VANILLA = 7
... CHOCOLATE = 4
... COOKIES = 9
... MINT = 3
...
>>> for shake in Shake:
... print(shake)
...
Shake.VANILLA
Shake.CHOCOLATE
Shake.COOKIES
Shake.MINT
Enumeration members are hashable, so they can be used in dictionaries and sets:
>>> apples = {}
>>> apples[Color.RED] = 'red delicious'
>>> apples[Color.GREEN] = 'granny smith'
>>> apples == {Color.RED: 'red delicious', Color.GREEN: 'granny smith'}
True
Sometimes it’s useful to access members in enumerations programmatically (i.e.
situations where Color.RED won’t do because the exact color is not known
at program-writing time). Enum allows such access:
>>> Color(1)
<Color.RED: 1>
>>> Color(3)
<Color.BLUE: 3>
If you want to access enum members by name, use item access:
>>> Color['RED']
<Color.RED: 1>
>>> Color['GREEN']
<Color.GREEN: 2>
If you have an enum member and need its name or value:
>>> member = Color.RED
>>> member.name
'RED'
>>> member.value
1
Having two enum members with the same name is invalid:
>>> class Shape(Enum):
... SQUARE = 2
... SQUARE = 3
...
Traceback (most recent call last):
...
TypeError: Attempted to reuse key: 'SQUARE'
However, two enum members are allowed to have the same value. Given two members A and B with the same value (and A defined first), B is an alias to A. By-value lookup of the value of A and B will return A. By-name lookup of B will also return A:
>>> class Shape(Enum):
... SQUARE = 2
... DIAMOND = 1
... CIRCLE = 3
... ALIAS_FOR_SQUARE = 2
...
>>> Shape.SQUARE
<Shape.SQUARE: 2>
>>> Shape.ALIAS_FOR_SQUARE
<Shape.SQUARE: 2>
>>> Shape(2)
<Shape.SQUARE: 2>
Note
Attempting to create a member with the same name as an already defined attribute (another member, a method, etc.) or attempting to create an attribute with the same name as a member is not allowed.
By default, enumerations allow multiple names as aliases for the same value. When this behavior isn’t desired, the following decorator can be used to ensure each value is used only once in the enumeration:
@enum.uniqueA class decorator specifically for enumerations. It searches an
enumeration’s __members__ gathering any aliases it finds; if any are
found ValueError is raised with the details:
>>> from enum import Enum, unique
>>> @unique
... class Mistake(Enum):
... ONE = 1
... TWO = 2
... THREE = 3
... FOUR = 3
...
Traceback (most recent call last):
...
ValueError: duplicate values found in <enum 'Mistake'>: FOUR -> THREE
If the exact value is unimportant you can use auto:
>>> from enum import Enum, auto
>>> class Color(Enum):
... RED = auto()
... BLUE = auto()
... GREEN = auto()
...
>>> list(Color)
[<Color.RED: 1>, <Color.BLUE: 2>, <Color.GREEN: 3>]
The values are chosen by _generate_next_value_(), which can be
overridden:
>>> class AutoName(Enum):
... def _generate_next_value_(name, start, count, last_values):
... return name
...
>>> class Ordinal(AutoName):
... NORTH = auto()
... SOUTH = auto()
... EAST = auto()
... WEST = auto()
...
>>> list(Ordinal)
[<Ordinal.NORTH: 'NORTH'>, <Ordinal.SOUTH: 'SOUTH'>, <Ordinal.EAST: 'EAST'>, <Ordinal.WEST: 'WEST'>]
Iterating over the members of an enum does not provide the aliases:
>>> list(Shape)
[<Shape.SQUARE: 2>, <Shape.DIAMOND: 1>, <Shape.CIRCLE: 3>]
The special attribute __members__ is an ordered dictionary mapping names
to members. It includes all names defined in the enumeration, including the
aliases:
>>> for name, member in Shape.__members__.items():
... name, member
...
('SQUARE', <Shape.SQUARE: 2>)
('DIAMOND', <Shape.DIAMOND: 1>)
('CIRCLE', <Shape.CIRCLE: 3>)
('ALIAS_FOR_SQUARE', <Shape.SQUARE: 2>)
The __members__ attribute can be used for detailed programmatic access to
the enumeration members. For example, finding all the aliases:
>>> [name for name, member in Shape.__members__.items() if member.name != name]
['ALIAS_FOR_SQUARE']
Enumeration members are compared by identity:
>>> Color.RED is Color.RED
True
>>> Color.RED is Color.BLUE
False
>>> Color.RED is not Color.BLUE
True
Ordered comparisons between enumeration values are not supported. Enum members are not integers (but see IntEnum below):
>>> Color.RED < Color.BLUE
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: '<' not supported between instances of 'Color' and 'Color'
Equality comparisons are defined though:
>>> Color.BLUE == Color.RED
False
>>> Color.BLUE != Color.RED
True
>>> Color.BLUE == Color.BLUE
True
Comparisons against non-enumeration values will always compare not equal
(again, IntEnum was explicitly designed to behave differently, see
below):
>>> Color.BLUE == 2
False
The examples above use integers for enumeration values. Using integers is short and handy (and provided by default by the Functional API), but not strictly enforced. In the vast majority of use-cases, one doesn’t care what the actual value of an enumeration is. But if the value is important, enumerations can have arbitrary values.
Enumerations are Python classes, and can have methods and special methods as usual. If we have this enumeration:
>>> class Mood(Enum):
... FUNKY = 1
... HAPPY = 3
...
... def describe(self):
... # self is the member here
... return self.name, self.value
...
... def __str__(self):
... return 'my custom str! {0}'.format(self.value)
...
... @classmethod
... def favorite_mood(cls):
... # cls here is the enumeration
... return cls.HAPPY
...
Then:
>>> Mood.favorite_mood()
<Mood.HAPPY: 3>
>>> Mood.HAPPY.describe()
('HAPPY', 3)
>>> str(Mood.FUNKY)
'my custom str! 1'
The rules for what is allowed are as follows: names that start and end with
a single underscore are reserved by enum and cannot be used; all other
attributes defined within an enumeration will become members of this
enumeration, with the exception of special methods (__str__(),
__add__(), etc.) and descriptors (methods are also descriptors).
Note: if your enumeration defines __new__() and/or __init__() then
whatever value(s) were given to the enum member will be passed into those
methods. See Planet for an example.
Subclassing an enumeration is allowed only if the enumeration does not define any members. So this is forbidden:
>>> class MoreColor(Color):
... PINK = 17
...
Traceback (most recent call last):
...
TypeError: Cannot extend enumerations
But this is allowed:
>>> class Foo(Enum):
... def some_behavior(self):
... pass
...
>>> class Bar(Foo):
... HAPPY = 1
... SAD = 2
...
Allowing subclassing of enums that define members would lead to a violation of some important invariants of types and instances. On the other hand, it makes sense to allow sharing some common behavior between a group of enumerations. (See OrderedEnum for an example.)
Enumerations can be pickled and unpickled:
>>> from test.test_enum import Fruit
>>> from pickle import dumps, loads
>>> Fruit.TOMATO is loads(dumps(Fruit.TOMATO))
True
The usual restrictions for pickling apply: picklable enums must be defined in the top level of a module, since unpickling requires them to be importable from that module.
Note
With pickle protocol version 4 it is possible to easily pickle enums nested in other classes.
It is possible to modify how Enum members are pickled/unpickled by defining
__reduce_ex__() in the enumeration class.
The Enum class is callable, providing the following functional API:
>>> Animal = Enum('Animal', 'ANT BEE CAT DOG')
>>> Animal
<enum 'Animal'>
>>> Animal.ANT
<Animal.ANT: 1>
>>> Animal.ANT.value
1
>>> list(Animal)
[<Animal.ANT: 1>, <Animal.BEE: 2>, <Animal.CAT: 3>, <Animal.DOG: 4>]
The semantics of this API resemble namedtuple. The first
argument of the call to Enum is the name of the enumeration.
The second argument is the source of enumeration member names. It can be a
whitespace-separated string of names, a sequence of names, a sequence of
2-tuples with key/value pairs, or a mapping (e.g. dictionary) of names to
values. The last two options enable assigning arbitrary values to
enumerations; the others auto-assign increasing integers starting with 1 (use
the start parameter to specify a different starting value). A
new class derived from Enum is returned. In other words, the above
assignment to Animal is equivalent to:
>>> class Animal(Enum):
... ANT = 1
... BEE = 2
... CAT = 3
... DOG = 4
...
The reason for defaulting to 1 as the starting number and not 0 is
that 0 is False in a boolean sense, but enum members all evaluate
to True.
Pickling enums created with the functional API can be tricky as frame stack implementation details are used to try and figure out which module the enumeration is being created in (e.g. it will fail if you use a utility function in separate module, and also may not work on IronPython or Jython). The solution is to specify the module name explicitly as follows:
>>> Animal = Enum('Animal', 'ANT BEE CAT DOG', module=__name__)
Warning
If module is not supplied, and Enum cannot determine what it is,
the new Enum members will not be unpicklable; to keep errors closer to
the source, pickling will be disabled.
The new pickle protocol 4 also, in some circumstances, relies on
__qualname__ being set to the location where pickle will be able
to find the class. For example, if the class was made available in class
SomeData in the global scope:
>>> Animal = Enum('Animal', 'ANT BEE CAT DOG', qualname='SomeData.Animal')
The complete signature is:
Enum(value='NewEnumName', names=<...>, *, module='...', qualname='...', type=<mixed-in class>, start=1)
| value: | What the new Enum class will record as its name. |
|---|---|
| names: | The Enum members. This can be a whitespace or comma separated string (values will start at 1 unless otherwise specified): 'RED GREEN BLUE' | 'RED,GREEN,BLUE' | 'RED, GREEN, BLUE'
or an iterator of names: ['RED', 'GREEN', 'BLUE']
or an iterator of (name, value) pairs: [('CYAN', 4), ('MAGENTA', 5), ('YELLOW', 6)]
or a mapping: {'CHARTREUSE': 7, 'SEA_GREEN': 11, 'ROSEMARY': 42}
|
| module: | name of module where new Enum class can be found. |
| qualname: | where in module new Enum class can be found. |
| type: | type to mix in to new Enum class. |
| start: | number to start counting at if only names are passed in. |
Changed in version 3.5: The start parameter was added.
The first variation of Enum that is provided is also a subclass of
int. Members of an IntEnum can be compared to integers;
by extension, integer enumerations of different types can also be compared
to each other:
>>> from enum import IntEnum
>>> class Shape(IntEnum):
... CIRCLE = 1
... SQUARE = 2
...
>>> class Request(IntEnum):
... POST = 1
... GET = 2
...
>>> Shape == 1
False
>>> Shape.CIRCLE == 1
True
>>> Shape.CIRCLE == Request.POST
True
However, they still can’t be compared to standard Enum enumerations:
>>> class Shape(IntEnum):
... CIRCLE = 1
... SQUARE = 2
...
>>> class Color(Enum):
... RED = 1
... GREEN = 2
...
>>> Shape.CIRCLE == Color.RED
False
IntEnum values behave like integers in other ways you’d expect:
>>> int(Shape.CIRCLE)
1
>>> ['a', 'b', 'c'][Shape.CIRCLE]
'b'
>>> [i for i in range(Shape.SQUARE)]
[0, 1]
The next variation of Enum provided, IntFlag, is also based
on int. The difference being IntFlag members can be combined
using the bitwise operators (&, |, ^, ~) and the result is still an
IntFlag member. However, as the name implies, IntFlag
members also subclass int and can be used wherever an int is
used. Any operation on an IntFlag member besides the bit-wise
operations will lose the IntFlag membership.
New in version 3.6.
Sample IntFlag class:
>>> from enum import IntFlag
>>> class Perm(IntFlag):
... R = 4
... W = 2
... X = 1
...
>>> Perm.R | Perm.W
<Perm.R|W: 6>
>>> Perm.R + Perm.W
6
>>> RW = Perm.R | Perm.W
>>> Perm.R in RW
True
It is also possible to name the combinations:
>>> class Perm(IntFlag):
... R = 4
... W = 2
... X = 1
... RWX = 7
>>> Perm.RWX
<Perm.RWX: 7>
>>> ~Perm.RWX
<Perm.-8: -8>
Another important difference between IntFlag and Enum is that
if no flags are set (the value is 0), its boolean evaluation is False:
>>> Perm.R & Perm.X
<Perm.0: 0>
>>> bool(Perm.R & Perm.X)
False
Because IntFlag members are also subclasses of int they can
be combined with them:
>>> Perm.X | 8
<Perm.8|X: 9>
The last variation is Flag. Like IntFlag, Flag
members can be combined using the bitwise operators (&, |, ^, ~). Unlike
IntFlag, they cannot be combined with, nor compared against, any
other Flag enumeration, nor int. While it is possible to
specify the values directly it is recommended to use auto as the
value and let Flag select an appropriate value.
New in version 3.6.
Like IntFlag, if a combination of Flag members results in no
flags being set, the boolean evaluation is False:
>>> from enum import Flag
>>> class Color(Flag):
... RED = auto()
... BLUE = auto()
... GREEN = auto()
...
>>> Color.RED & Color.GREEN
<Color.0: 0>
>>> bool(Color.RED & Color.GREEN)
False
Individual flags should have values that are powers of two (1, 2, 4, 8, ...), while combinations of flags won’t:
>>> class Color(Flag):
... RED = auto()
... BLUE = auto()
... GREEN = auto()
... WHITE = RED | BLUE | GREEN
...
>>> Color.WHITE
<Color.WHITE: 7>
Giving a name to the “no flags set” condition does not change its boolean value:
>>> class Color(Flag):
... BLACK = 0
... RED = auto()
... BLUE = auto()
... GREEN = auto()
...
>>> Color.BLACK
<Color.BLACK: 0>
>>> bool(Color.BLACK)
False
Note
For the majority of new code, Enum and Flag are strongly
recommended, since IntEnum and IntFlag break some
semantic promises of an enumeration (by being comparable to integers, and
thus by transitivity to other unrelated enumerations). IntEnum
and IntFlag should be used only in cases where Enum and
Flag will not do; for example, when integer constants are replaced
with enumerations, or for interoperability with other systems.
While IntEnum is part of the enum module, it would be very
simple to implement independently:
class IntEnum(int, Enum):
pass
This demonstrates how similar derived enumerations can be defined; for example
a StrEnum that mixes in str instead of int.
Some rules:
Enum, mix-in types must appear before
Enum itself in the sequence of bases, as in the IntEnum
example above.Enum can have members of any type, once you mix in an
additional type, all the members must have values of that type, e.g.
int above. This restriction does not apply to mix-ins which only
add methods and don’t specify another data type such as int or
str.value attribute is not the
same as the enum member itself, although it is equivalent and will compare
equal.Enum class’s
__str__() and __repr__() respectively; other codes (such as
%i or %h for IntEnum) treat the enum member as its mixed-in type.str.format(),
and format() will use the mixed-in
type’s __format__(). If the Enum class’s str() or
repr() is desired, use the !s or !r format codes.While Enum, IntEnum, IntFlag, and Flag are
expected to cover the majority of use-cases, they cannot cover them all. Here
are recipes for some different types of enumerations that can be used directly,
or as examples for creating one’s own.
In many use-cases one doesn’t care what the actual value of an enumeration is. There are several ways to define this type of simple enumeration:
auto for the valueobject as the value__new__() to replace the
tuple with an int valueUsing any of these methods signifies to the user that these values are not important, and also enables one to add, remove, or reorder members without having to renumber the remaining members.
Whichever method you choose, you should provide a repr() that also hides
the (unimportant) value:
>>> class NoValue(Enum):
... def __repr__(self):
... return '<%s.%s>' % (self.__class__.__name__, self.name)
...
auto¶Using auto would look like:
>>> class Color(NoValue):
... RED = auto()
... BLUE = auto()
... GREEN = auto()
...
>>> Color.GREEN
<Color.GREEN>
object¶Using object would look like:
>>> class Color(NoValue):
... RED = object()
... GREEN = object()
... BLUE = object()
...
>>> Color.GREEN
<Color.GREEN>
Using a string as the value would look like:
>>> class Color(NoValue):
... RED = 'stop'
... GREEN = 'go'
... BLUE = 'too fast!'
...
>>> Color.GREEN
<Color.GREEN>
>>> Color.GREEN.value
'go'
__new__()¶Using an auto-numbering __new__() would look like:
>>> class AutoNumber(NoValue):
... def __new__(cls):
... value = len(cls.__members__) + 1
... obj = object.__new__(cls)
... obj._value_ = value
... return obj
...
>>> class Color(AutoNumber):
... RED = ()
... GREEN = ()
... BLUE = ()
...
>>> Color.GREEN
<Color.GREEN>
>>> Color.GREEN.value
2
An ordered enumeration that is not based on IntEnum and so maintains
the normal Enum invariants (such as not being comparable to other
enumerations):
>>> class OrderedEnum(Enum):
... def __ge__(self, other):
... if self.__class__ is other.__class__:
... return self.value >= other.value
... return NotImplemented
... def __gt__(self, other):
... if self.__class__ is other.__class__:
... return self.value > other.value
... return NotImplemented
... def __le__(self, other):
... if self.__class__ is other.__class__:
... return self.value <= other.value
... return NotImplemented
... def __lt__(self, other):
... if self.__class__ is other.__class__:
... return self.value < other.value
... return NotImplemented
...
>>> class Grade(OrderedEnum):
... A = 5
... B = 4
... C = 3
... D = 2
... F = 1
...
>>> Grade.C < Grade.A
True
Raises an error if a duplicate member name is found instead of creating an alias:
>>> class DuplicateFreeEnum(Enum):
... def __init__(self, *args):
... cls = self.__class__
... if any(self.value == e.value for e in cls):
... a = self.name
... e = cls(self.value).name
... raise ValueError(
... "aliases not allowed in DuplicateFreeEnum: %r --> %r"
... % (a, e))
...
>>> class Color(DuplicateFreeEnum):
... RED = 1
... GREEN = 2
... BLUE = 3
... GRENE = 2
...
Traceback (most recent call last):
...
ValueError: aliases not allowed in DuplicateFreeEnum: 'GRENE' --> 'GREEN'
Note
This is a useful example for subclassing Enum to add or change other
behaviors as well as disallowing aliases. If the only desired change is
disallowing aliases, the unique() decorator can be used instead.
If __new__() or __init__() is defined the value of the enum member
will be passed to those methods:
>>> class Planet(Enum):
... MERCURY = (3.303e+23, 2.4397e6)
... VENUS = (4.869e+24, 6.0518e6)
... EARTH = (5.976e+24, 6.37814e6)
... MARS = (6.421e+23, 3.3972e6)
... JUPITER = (1.9e+27, 7.1492e7)
... SATURN = (5.688e+26, 6.0268e7)
... URANUS = (8.686e+25, 2.5559e7)
... NEPTUNE = (1.024e+26, 2.4746e7)
... def __init__(self, mass, radius):
... self.mass = mass # in kilograms
... self.radius = radius # in meters
... @property
... def surface_gravity(self):
... # universal gravitational constant (m3 kg-1 s-2)
... G = 6.67300E-11
... return G * self.mass / (self.radius * self.radius)
...
>>> Planet.EARTH.value
(5.976e+24, 6378140.0)
>>> Planet.EARTH.surface_gravity
9.802652743337129
Enums have a custom metaclass that affects many aspects of both derived Enum classes and their instances (members).
The EnumMeta metaclass is responsible for providing the
__contains__(), __dir__(), __iter__() and other methods that
allow one to do things with an Enum class that fail on a typical
class, such as list(Color) or some_var in Color. EnumMeta is
responsible for ensuring that various other methods on the final Enum
class are correct (such as __new__(), __getnewargs__(),
__str__() and __repr__()).
The most interesting thing about Enum members is that they are singletons.
EnumMeta creates them all while it is creating the Enum
class itself, and then puts a custom __new__() in place to ensure
that no new ones are ever instantiated by returning only the existing
member instances.
__dunder__ names¶__members__ is an OrderedDict of member_name:member
items. It is only available on the class.
__new__(), if specified, must create and return the enum members; it is
also a very good idea to set the member’s _value_ appropriately. Once
all the members are created it is no longer used.
_sunder_ names¶_name_ – name of the member_value_ – value of the member; can be set / modified in __new___missing_ – a lookup function used when a value is not found; may be
overridden_order_ – used in Python 2/3 code to ensure member order is consistent
(class attribute, removed during class creation)_generate_next_value_ – used by the Functional API and by
auto to get an appropriate value for an enum member; may be
overriddenNew in version 3.6: _missing_, _order_, _generate_next_value_
To help keep Python 2 / Python 3 code in sync an _order_ attribute can
be provided. It will be checked against the actual order of the enumeration
and raise an error if the two do not match:
>>> class Color(Enum):
... _order_ = 'RED GREEN BLUE'
... RED = 1
... BLUE = 3
... GREEN = 2
...
Traceback (most recent call last):
...
TypeError: member order does not match _order_
Note
In Python 2 code the _order_ attribute is necessary as definition
order is lost before it can be recorded.
Enum member type¶Enum members are instances of their Enum class, and are
normally accessed as EnumClass.member. Under certain circumstances they
can also be accessed as EnumClass.member.member, but you should never do
this as that lookup may fail or, worse, return something besides the
Enum member you are looking for (this is another good reason to use
all-uppercase names for members):
>>> class FieldTypes(Enum):
... name = 0
... value = 1
... size = 2
...
>>> FieldTypes.value.size
<FieldTypes.size: 2>
>>> FieldTypes.size.value
2
Changed in version 3.5.
Enum classes and members¶Enum members that are mixed with non-Enum types (such as
int, str, etc.) are evaluated according to the mixed-in
type’s rules; otherwise, all members evaluate as True. To make your
own Enum’s boolean evaluation depend on the member’s value add the following to
your class:
def __bool__(self):
return bool(self.value)
Enum classes with methods¶If you give your Enum subclass extra methods, like the Planet
class above, those methods will show up in a dir() of the member,
but not of the class:
>>> dir(Planet)
['EARTH', 'JUPITER', 'MARS', 'MERCURY', 'NEPTUNE', 'SATURN', 'URANUS', 'VENUS', '__class__', '__doc__', '__members__', '__module__']
>>> dir(Planet.EARTH)
['__class__', '__doc__', '__module__', 'name', 'surface_gravity', 'value']
Flag¶If a combination of Flag members is not named, the repr() will include
all named flags and all named combinations of flags that are in the value:
>>> class Color(Flag):
... RED = auto()
... GREEN = auto()
... BLUE = auto()
... MAGENTA = RED | BLUE
... YELLOW = RED | GREEN
... CYAN = GREEN | BLUE
...
>>> Color(3) # named combination
<Color.YELLOW: 3>
>>> Color(7) # not named combination
<Color.CYAN|MAGENTA|BLUE|YELLOW|GREEN|RED: 7>