Make single Payment of multiple Invoice

Hello there,

I have created a button “Get Item From” in which it will list all the Purchase Invoice but when I try to “Get Item”, It will show me error that “ImportError: No module named purchase_invoice.purchase_invoice”. So I have checked all the file but I did not get anything. If anyone knows then please help me.
Thanks in advance.

Here is the snapshot:

Here is the Traceback:
Traceback (most recent call 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 22, in handle
data = execute_cmd(cmd)
File “/home/frappe/frappe-bench/apps/frappe/frappe/handler.py”, line 53, in execute_cmd
return frappe.call(method, **frappe.form_dict)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 935, in call
return fn(*args, **newargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/mapper.py”, line 33, in map_docs
method = frappe.get_attr(method)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 915, in get_attr
return getattr(get_module(modulename), methodname)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 700, in get_module
return importlib.import_module(modulename)
File “/usr/lib/python2.7/importlib/init.py”, line 37, in import_module
import(name)
ImportError: No module named purchase_invoice.purchase_invoice