General Utils

UNDEFINED

djem.UNDEFINED

Added in version 0.7.

The UNDEFINED constant is a falsey value designed for use in argument default values, for situations in which any value given (including traditional argument default values such as None) have an explicit meaning.

from djem import UNDEFINED

def make_thing(name, label=UNDEFINED):

    # None, the empty string, or False could indicate "no label" and need
    # to be distinguished from no value being provided
    if label is UNDEFINED:
        label = name

    ...

It can also be used in more generic conditional statements:

from djem import UNDEFINED

value = UNDEFINED

if value:
    print('truthy')
else:
    print('falsey')

# output: 'falsey'