enum

[ast]

Hi

Below an example of enum which defines an __init__
method. 

https://docs.python.org/3.5/library/enum.html#planet

Documentation says that the value of the enum 
members will be passed to this method.

But in that case __init__ waits for two arguments, mass
and radius, while enum member's value is a tuple. 

It seems that there is a tuple unpacking, but it is
not documented, that's not clear 

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)