Uncaught Error: NameError: name 'true' is not defined

Question

I want to add a custom field in sale.order in oddo 11. But all of sudden this unexpected error "Uncaught Error: NameError: name 'true' is not defined " is showed whenever i pull up sales order.

manifest.py

{
'name': 'Screen Printing',
'version': '1.0',
'description': """
This module adds functionality for screen printing companies.
===============================================
""",
'author': 'Ahmed Sheikh',
'depends': ['base','sale'],
'demo': [],
'data': ['silkworm_views.xml'],
'installable': True,
'auto_install': False,
}

init.py

from . import silkworm

silkworm.py

 from odoo import models, fields

 class silkworm_sale_order(models.Model):
_inherit = 'sale.order'

daterequired = fields.Date('Date Required', required=True)
rush = fields.Boolean('Rush Order')

silkworm_views.xml

 <?xml version="1.0" encoding="utf-8"?>
 <odoo>
 <data>
 <record id="sale_view_order_form" model="ir.ui.view">
     <field name="model">sale.order</field>
     <field name="inherit_id" ref="sale.view_order_form"/>
     <field name="arch" type="xml">
     <field name="payment_term_id" position="after">
     <field name="daterequired"/>
     <field name="rush"/>
     </field>
     </field>
    </record>
    </data>
   </odoo>

here is the full error message:

   http://localhost:8069/web/content/492-440210e/web.assets_backend.js:144
   Traceback:
   Error: NameError: name 'true' is not defined
   at PY_ensurepy (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:144:65)
   at Object.py.evaluate (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:259:8)
   at Object.py.evaluate (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:265:111)
   at Object.py.evaluate (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:267:99)
   at Object.py.eval (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:272:284)
   at http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:380:136
   at Function._.each._.forEach (http://localhost:8069/web/content/368- 
   f2074dd/web.assets_common.js:12:558)
   at _.<computed> [as each] (http://localhost:8069/web/content/368- 
   f2074dd/web.assets_common.js:69:526)
   at eval_domains (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:379:265)
   at Object.pyeval [as eval] (http://localhost:8069/web/content/492- 
   440210e/web.assets_backend.js:393:24)