Problem in upgrading V12 ValidationError can not change the value of Valuation Method

Getting this error when trying to upgrade the erpNEXT v12 from V11.

please find the details.

Traceback (most recent call last):
File “/usr/lib/python2.7/runpy.py”, line 162, in _run_module_as_main
main”, fname, loader, pkg_name)
File “/usr/lib/python2.7/runpy.py”, line 72, in _run_code
exec code in run_globals
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py”, line 97, in
main()
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/bench_helper.py”, line 18, in main
click.Group(commands=commands)(prog_name=‘bench’)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 764, in call
return self.main(*args, **kwargs)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 717, in main
rv = self.invoke(ctx)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 1137, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 1137, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 956, in invoke
return ctx.invoke(self.callback, **ctx.params)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/core.py”, line 555, in invoke
return callback(*args, **kwargs)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/click/decorators.py”, line 17, in new_func
return f(get_current_context(), *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/commands/init.py”, line 25, in _func
ret = f(frappe._dict(ctx.obj), *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/commands/site.py”, line 233, in migrate
migrate(context.verbose, rebuild_website=rebuild_website, skip_failing=skip_failing)
File “/home/frappe/frappe-bench/apps/frappe/frappe/migrate.py”, line 48, in migrate
frappe.modules.patch_handler.run_all(skip_failing)
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py”, line 41, in run_all
run_patch(patch)
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py”, line 30, in run_patch
if not run_single(patchmodule = patch):
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py”, line 71, in run_single
return execute_patch(patchmodule, method, methodargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/modules/patch_handler.py”, line 91, in execute_patch
frappe.get_attr(patchmodule.split()[0] + “.execute”)()
File “/home/frappe/frappe-bench/apps/erpnext/erpnext/patches/v12_0/move_item_tax_to_item_tax_template.py”, line 44, in execute
item.save()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 271, in save
return self._save(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 324, in _save
self.run_post_save_methods()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 917, in run_post_save_methods
self.run_method(“on_update”)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 786, in run_method
out = Document.hook(fn)(self, *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 1056, in composer
return composed(self, method, *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 1039, in runner
add_to_return_value(self, fn(self, *args, **kwargs))
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 780, in
fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/erpnext/erpnext/stock/doctype/item/item.py”, line 139, in on_update
self.update_variants()
File “/home/frappe/frappe-bench/apps/erpnext/erpnext/stock/doctype/item/item.py”, line 764, in update_variants
update_variants(variants, self, publish_progress=False)
File “/home/frappe/frappe-bench/apps/erpnext/erpnext/stock/doctype/item/item.py”, line 1119, in update_variants
variant.save()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 271, in save
return self._save(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 307, in save
self.run_before_save_methods()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 886, in run_before_save_methods
self.run_method(“validate”)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 786, in run_method
out = Document.hook(fn)(self, *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 1056, in composer
return composed(self, method, *args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 1039, in runner
add_to_return_value(self, fn(self, *args, **kwargs))
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 780, in
fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/erpnext/erpnext/stock/doctype/item/item.py”, line 126, in validate
self.cant_change()
File “/home/frappe/frappe-bench/apps/erpnext/erpnext/stock/doctype/item/item.py”, line 864, in cant_change
frappe.throw(
(“As there are existing transactions against item {0}, you can not change the value of {1}”).format(self.name, frappe.bold(self.meta.get_label(field))))
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 360, in throw
msgprint(msg, raise_exception=exc, title=title, indicator=‘red’)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 346, in msgprint
_raise_exception()
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 315, in _raise_exception
raise raise_exception(msg)
frappe.exceptions.ValidationError: As there are existing transactions against item PARD001-70023C, you can not change the value of Valuation Method
shreyasdk@instance-1:/home/frappe/frappe-bench$