I had inherited the model sale.order in my custom module and I want to customize it according to my requirements. some fields I can hide but some of them I cannot hide 

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

the manifest file is ok with depends...

and I had also defined that field in my module but also doesn't work

the error is

ile "/home/nazir/odoo13/odoo/addons/base/models/ir_ui_view.py", line 614, in raise_view_error
    raise ValueError(message)
odoo.tools.convert.ParseError: "Element '' cannot be located in parent view
Error context:
View `sale.order.form`
[view_id: 1692, xml_id: pharmacy_management_system.sale_template_form_inherit, model: sale.order, parent_id: 753]" while parsing /home/nazir/odoo13/custome_addons/pharmacy_management_system/views/inherited_sales.xml:2, near