Installation New Apps Error. Please Help me resolve this

Hi All, i’m new in ERPNext. i follow the instruction How to Make New App in ERPNext(url: https://frappe.github.io/frappe/user/en/tutorial/new-app.html ) and when its done i get this Error. I do not know how do i get this Error. Totally No Idea. Please Help me resolve this. What should i do to resolve this error.

Traceback (innermost last):
File “/home/frappe/frappe-bench/apps/frappe/frappe/app.py”, line 57, in application
response = frappe.handler.handle()
File “/home/frappe/frappe-bench/apps/frappe/frappe/handler.py”, line 19, in handle
execute_cmd(cmd)
File “/home/frappe/frappe-bench/apps/frappe/frappe/handler.py”, line 36, in execute_cmd
ret = frappe.call(method, *frappe.form_dict)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 806, in call
return fn(args, **newargs)
TypeError: get() takes exactly 1 argument (0 given)

@moulinozawa can you check the versions of frappe and erpnext that you are using?

type: bench version from frappe-bench folder

Hello Sir/Madam Anand,

This is what i got:

Ubuntu 14.04.4 LTS
erpnext 6.27.22
erpnext_shopify 1.5.5
frappe 6.27.21

when i type bench version

@moulinozawa what’s the output of :

cd /home/frappe/frappe-bench/apps/frappe && git branch
cd /home/frappe/frappe-bench/apps/erpnext && git branch

When i type this one: cd /home/frappe/frappe-bench/apps/frappe && git branch
it show: master

and

When i type this one: cd /home/frappe/frappe-bench/apps/erpnext && git branch
it show: master

Please Help me resolve this