def get_doctypes():
    # Add method here to add ability to validate and write a validator for it.
    return [
        ('1', 'Default'),
        ('2', 'Credit Card'),
        ('3', 'Book'),
    ]
returns a list of tuple for possible document types
dataset/ETHPy150Open adlibre/Adlibre-DMS/adlibre_dms/apps/core/models.py/get_doctypes