Hi Everyone !
I am trying to create dynamic view ,  so i want to create views in python side . But when i try to save the view the "arch_base" field is not set . Can someone tell me what's the problem ? Here is my function 

@api.onchange('field_id')
def create_validation_button(self):
    model = self.field_id.model_id.model
    model_view = self.env['ir.ui.view'].search([("model", "=", model), ('type', "=", "form")])
    arch = '<xpath expr="//header" postition="inside"><button string="Add Followers" type="object" name="add_project_followers" /></xpath>'
    if model_view:
        self.view_id = None
        self.env['ir.ui.view'].search(
            [("model", "=", model), ('name', "=", 'validation.' + model_view.name)]).unlink()
        view_data = {'name': 'validation.' + model_view.name, 'type': 'form', 'model': model, 'priority': 1,
                     'inherit_id': model_view.id,
                     'mode': 'extension',
                     'arch_base': arch.encode('utf-8')}
        view = self.env["ir.ui.view"].create(view_data)
        self.view_id = view