"Get By or Add" Pattern

Frequently when initializing data, one might find this particular pattern emerging:

my = MyEntity.get_by(name="John", email="john@example.com")
if not my:
    # create it
    my = MyEntity(name="John", email="john@example.com")
    my.password = "default"

If you find you encounter this pattern frequently, try patching Elixir.Entity with the following:

from elixir import Entity

def get_by_or_init(cls, if_new_set={}, **params):
	"""Call get_by; if no object is returned, initialize an
	object with the same parameters.  If a new object was
	created, set any initial values."""
	
	result = cls.get_by(**params)
	if not result:
		result = cls(**params)
		result.set(**if_new_set)
	return result

Entity.get_by_or_init = classmethod(get_by_or_init)

Now you may easily initialize your data with a simple single call and much less repetition.

my = MyEntity.get_by_or_init(
    name="John",
    email="john@example.com",
    if_new_set=dict(password="default")
)