Odoo my_module simplification

module_core.py

# code snip for clarification
class module_core_user_input(osv.Model):
    _name = "module_core.user_input"
    _description = 'Module Core User Input'

    _columns = {
      'master_document_id': fields.many2one('qdi_core.survey', 'Master Document', required=True,
                                    readonly=1, ondelete='restrict'),
      'user_input_line_ids': fields.one2many('module_core.user_input_line',
                                              'user_input_id', 'Inputs'),


class module_core_user_input_line(osv.Model):
  _name = 'module_core.user_input_line'
  _description = 'Module description'
  
  _columns = {
    'user_input_id': fields.many2one('module_core.user_input', ondelete='cascade', required='),
    'item_id': fields.many2one('module_core.item', 'Item to r'
                                ondelete='restrict', required=1),
    'container_id': fields.many2one('module_core.container', 'Container of item',
                                ondelete='restrict', required=1),
    'group_id': fields.many2one('module_core.group_group', 'Group of Container',
                                ondelete='restrict', required=1),
    'master_document_id': fields.related('user_input_id', 'master_document_id',
                                          type="many2one", relation="module_core.master_document",
                                          string='Document Master', store=True),
    }