'Determine inherited fields.'

@api.model
def _add_inherited_fields(self):

    fields = {}
    for (parent_model, parent_field) in self._inherits.iteritems():
        parent = self.env[parent_model]
        for (name, field) in parent._fields.iteritems():
            fields[name] = field.new(inherited=True, related=(parent_field, name), related_sudo=False, copy=field.copy)
    for (name, field) in fields.iteritems():
        if (name not in self._fields):
            self._add_field(name, field)
