500: Internal Server Error

Traceback

Traceback (most recent call last):
  File "/odoo/odoo-server/odoo/addons/base/models/ir_http.py", line 234, in _dispatch
    result = request.dispatch()
  File "/odoo/odoo-server/odoo/http.py", line 809, in dispatch
    r = self._call_function(**self.params)
  File "/odoo/odoo-server/odoo/http.py", line 350, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/odoo/odoo-server/odoo/service/model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "/odoo/odoo-server/odoo/http.py", line 339, in checked_call
    result = self.endpoint(*a, **kw)
  File "/odoo/odoo-server/odoo/http.py", line 915, in __call__
    return self.method(*args, **kw)
  File "/odoo/odoo-server/odoo/http.py", line 515, in response_wrap
    response = f(*args, **kw)
  File "/odoo/custom/addons/qrcode_table/controllers/main.py", line 31, in table_booking
    print("...........pax..........", request.session['pax'], beverages, pos_cate_id)
KeyError: 'pax'