in create python code in my modulue here is code

    from osv import osv , fields
     class asset_allocation(osv.osv):
   _name = 'asset.allocation'
   _description = 'Asset Allocation'
   _columns = {
    'asset_id': fields.many2one('account.asset.asset', 'Asset', required=True),
    'employee_id': fields.many2one('hr.employee', 'Employee', required=True),
    'asset_status': fields.date.time( 'Status', required=True,),
    'note': fields.text('Note'),
     }

     asset_allocation()

Error

Unresolved import: fields

Undefined variable from import: osv