500: Internal Server Error

Traceback

Traceback (most recent call last):
  File "/home/ubuntu/odoo/odoo/addons/base/models/ir_http.py", line 229, in _dispatch
    result = request.dispatch()
  File "/home/ubuntu/odoo/odoo/http.py", line 804, in dispatch
    r = self._call_function(**self.params)
  File "/home/ubuntu/odoo/odoo/http.py", line 345, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/ubuntu/odoo/odoo/service/model.py", line 93, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/ubuntu/odoo/odoo/http.py", line 338, in checked_call
    result = self.endpoint(*a, **kw)
  File "/home/ubuntu/odoo/odoo/http.py", line 910, in __call__
    return self.method(*args, **kw)
  File "/home/ubuntu/odoo/odoo/http.py", line 510, in response_wrap
    response = f(*args, **kw)
  File "/home/ubuntu/cua/atharva_theme_general/controllers/main.py", line 55, in shop
    raise NotFound()
NameError: name 'NotFound' is not defined