I have these models:

class bsi_production_order(models.Model):
    _name = 'bsi.production.order'

    @api.model
    def create(self, vals):
        if vals.get('name', 'New') == 'New':
            if vals.get('production_type') == 'budgeted':
                vals['name'] = self.env['ir.sequence'].next_by_code('bsi.production.budgeted') or '/'
            elif vals.get('production_type') == 'nonbudgeted':
                vals['name'] = self.env['ir.sequence'].next_by_code('bsi.production.non_budgeted') or '/'
            elif vals.get('production_type') == 'direct':
                vals['name'] = self.env['ir.sequence'].next_by_code('bsi.production.direct') or '/'
        return super(bsi_production_order, self).create(vals)

    name = fields.Char('Reference', required=True, index=True, copy=False, readonly='True', default='New')
    date = fields.Date(string="Production Date")
    production_type = fields.Selection([
        ('budgeted','Budgeted'),
        ('nonbudgeted','Non Budgeted'),
        ('direct','Direct Order'),
    ], string='Type of Order', index=True,  
    track_visibility='onchange', copy=False,
    help=" ")
    notes = fields.Text(string="Notes")
    order_lines = fields.One2many('bsi.production.order.lines', 'production_order', states={'finished': [('readonly', True)], 'cancel': [('readonly', True)]}, string="Order lines", copy=True)
print_orders = fields.One2many('bsi.print.order', 'production_orders', string="Print Orders")
state = fields.Selection([
        ('draft','Draft'),
        ('start','Started'),
        ('inprogress','In progress'),
        ('print_order_inprogress','Print Order In Progress'),
        ('finished','Finished'),
        ('cancel','Cancel'),
    ], string='State', index=True,  
    track_visibility='onchange', copy=False,
    help=" ")

class bsi_print_order(models.Model):
    _name = 'bsi.print.order'

    @api.model
    def create(self, vals):
        if vals.get('name', 'New') == 'New':
            vals['name'] = self.env['ir.sequence'].next_by_code('bsi.print.order') or '/'
        return super(bsi_print_order, self).create(vals)

    name = fields.Char('Reference', required=True, index=True, copy=False, readonly='True', default='New')
    date = fields.Date(string="Print Date")
    origin = fields.Char(string="Origin")
    production_orders = fields.Many2one('bsi.production.order', ondelete='cascade', string="Production Order")
    order_lines = fields.One2many('bsi.print.order.lines', 'print_order', string="Order lines")
    book_block = fields.Boolean(string="Book Block")
    binding = fields.Boolean(string="Binding")
    edging = fields.Boolean(string="Edging")
    contract_worksheet = fields.One2many('mrp.worksheet.contract', 'printer_order', string="Worksheet calculation")
    state = fields.Selection([
        ('draft','Draft'),
        ('awaitingraw','Awaiting raw materials'),
        ('wip','Work in Progress'),
        ('delivered','Delivered'),
        ('cancel','Cancel'),
    ], string="State")
    notes = fields.Text(string="Notes")

And this method, which belongs to bsi.production.order , it has to create a bsi.print.orderfrom it:

@api.multi
def create_printy(self):
    copy_record = self.env['bsi.print.order'] 
    for record in self:

        order_lines = []
        for rec in record.order_lines:
            order_lines.append(
            (0,0,
            {
                'isbn': rec.isbn.id,
                'consumed_qty': rec.qty,
                }
            ))

        copy_record.create({
            'state' : 'draft', 
            'order_lines': order_lines, 
        })

What is the problem? The problem is that, on bsi.production.order the state from which this function is visible (the button) is inprogress, now, this state doesn't exist on bsi.print.order, but, as You can see, on copy_record.create, I've passed 'state' as 'draft', but it doesn't works, it throws me:

ValidateError

Error while validating constraint

Wrong value for bsi.print.order.state: 'inprogress'

I mean, it's obvious, but not so much, because the bsi.print.order should be created on draftstate.

What am I doing wrong?