Packing Slip Error

I have an Item that is configured with UOM:

  • pcs with conversion factor 1
  • box with conversion factor 10

I have made Delivery note with 1000 pcs in it.

When i create Packing slip, and I specify from package 1 to package 100, system throw this error:

Traceback (most recent call last):
  File "/home/erp/nerp/apps/frappe/frappe/desk/form/save.py", line 22, in savedocs
    doc.save()
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 260, in save
    return self._save(*args, **kwargs)
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 283, in _save
    self.insert()
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 222, in insert
    self.run_before_save_methods()
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 876, in run_before_save_methods
    self.run_method("validate")
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 772, in run_method
    out = Document.hook(fn)(self, *args, **kwargs)
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 1048, in composer
    return composed(self, method, *args, **kwargs)
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 1031, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 766, in <lambda>
    fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
  File "/home/erp/nerp/apps/erpnext/erpnext/stock/doctype/packing_slip/packing_slip.py", line 25, in validate
    self.validate_case_nos()
  File "/home/erp/nerp/apps/erpnext/erpnext/stock/doctype/packing_slip/packing_slip.py", line 52, in validate_case_nos
    elif self.from_case_no > self.to_case_no:
TypeError: '>' not supported between instances of 'int' and 'str'

Traceback (most recent call last):
  File "/home/erp/nerp/apps/frappe/frappe/app.py", line 61, in application
    response = frappe.handler.handle()
  File "/home/erp/nerp/apps/frappe/frappe/handler.py", line 21, in handle
    data = execute_cmd(cmd)
  File "/home/erp/nerp/apps/frappe/frappe/handler.py", line 56, in execute_cmd
    return frappe.call(method, **frappe.form_dict)
  File "/home/erp/nerp/apps/frappe/frappe/__init__.py", line 1027, in call
    return fn(*args, **newargs)
  File "/home/erp/nerp/apps/frappe/frappe/desk/form/save.py", line 22, in savedocs
    doc.save()
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 260, in save
    return self._save(*args, **kwargs)
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 283, in _save
    self.insert()
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 222, in insert
    self.run_before_save_methods()
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 876, in run_before_save_methods
    self.run_method("validate")
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 772, in run_method
    out = Document.hook(fn)(self, *args, **kwargs)
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 1048, in composer
    return composed(self, method, *args, **kwargs)
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 1031, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "/home/erp/nerp/apps/frappe/frappe/model/document.py", line 766, in <lambda>
    fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
  File "/home/erp/nerp/apps/erpnext/erpnext/stock/doctype/packing_slip/packing_slip.py", line 25, in validate
    self.validate_case_nos()
  File "/home/erp/nerp/apps/erpnext/erpnext/stock/doctype/packing_slip/packing_slip.py", line 52, in validate_case_nos
    elif self.from_case_no > self.to_case_no:
TypeError: '>' not supported between instances of 'int' and 'str'

What’s wrong?
Is it a bug or I do something wrong?