What does the following expression do?

Question

What does the following expression do?

default=lambda self: ('New')

The exact expression is:

book_internal_code = fields.Char(
        string='Book Code', required=True, copy=False, readonly=True, index=True, default=lambda self: ('New'))

Answer 1

It is same as default='New'

But it creates a lambta that is executed when record is created. For example default=lambda self: self.env.user sets default value as current user