Where is OSCAR_DEFAULT_CURRENCY set?

Im trying to set ecommerce to run on Euros instead of the default US dollar.

It seems as though this parameter is set in
settings.OSCAR_DEFAULT_CURRENCY
This variable is used in ecommerce/courses/models.py and ecommerce/extensions/checkout/utils.py

Where is this settings file?
In the event of changing this settings file, do we need to recompile ecommerce?

It’s under ecommerce/ecommerce/settings/_oscar.py

Thanks @sambapete.

Once the _oscar.py file is amended, do I need to recompile any specific assets?

How do I recompile oscar/ecommerce assets?