tuttle

from trytond.model import ModelView, ModelSQL, fields
from trytond.pool import PoolMeta
# list of all classes in the file
__all__ = ['Book']
__metaclass__ = PoolMeta


class Book(ModelSQL, ModelView):
    # description (mandatory on first declaration)
    'Book'
    # Internal class name. Always used as a reference inside Tryton
    # default: '<module_name>.<class_name>' on Tryton
    # becomes '<module_name>_<class_name>' in the database
    __name__ = 'library.book'

    renter = fields.Char('Rented by', depends=['available'])
    available = fields.Boolean('Available for rent', depends=['renter'])

    @staticmethod
    def default_renter():
        return 'Chris. that is me!??!'

    @fields.depends('available')
    def on_change_renter(self, name=None):
        if self.renter:
            return {'available': False}
        else:
            return {'available': True}
    """
        if self.renter:
            self.available = False
        else:
            self.available = True
    """

    """
    @fields.depends('renter')
    def on_change_available(self):
        if self.available:
            return {'renter': 'Chris'}
        else:
            return {'renter': ''}
    """