Simplify Code.attributes type hint

[phackstock]

closes #191.

Mostly self explanatory, since Code.attributes does no longer need to support more complex region aggregation related data structures we can simplify the type hint.

[danielhuppmann]

Just to be sure, this typehint has no functional implications, right?

[phackstock]

Just to be sure, this typehint has no functional implications, right?

In the pure python sense this does not have any implications. By using pydantic it can have some functional implications. In the order of definition of options for data types in Union, pydantic will attempt type conversion.

As an example if we have:

from pydantic import BaseModel

class A(BaseModel):
    a: Union[int, str]

instance_A = A(a = "3") 
print(type(A.a)) >>> "int"

pydantic converts the string "3" into the integer 3.

This might have actually had a functional use in the past where we had attributes such as check-aggregate in the attributes object. Now that this is only used to hold additional, non-nomenclature functional information, it should not have any functional implications.

[danielhuppmann]

Thanks @phackstock, looks good!

[phackstock]

Seems like resolving the merge conflicts blew up something, I'll investigate.