ModuleNotFoundError: No module named 'frappe.website.render'

[SunilKrishnan]

Describe the bug
A clear and concise description of what the bug is.

Installing frappe_pwa...
Updating DocTypes for frappe_pwa : [========================================] 100%
An error occurred while installing frappe_pwa: No module named 'frappe.website.render'
Traceback (most recent call last):
File "apps/frappe/frappe/commands/site.py", line 342, in install_app
_install_app(app, verbose=context.verbose)
File "apps/frappe/frappe/installer.py", line 165, in install_app
add_to_installed_apps(name)
File "apps/frappe/frappe/installer.py", line 192, in add_to_installed_apps
post_install(rebuild_website)
File "apps/frappe/frappe/installer.py", line 343, in post_install
init_singles()
File "apps/frappe/frappe/installer.py", line 367, in init_singles
doc.save()
File "apps/frappe/frappe/model/document.py", line 285, in save
return self._save(*args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 307, in _save
return self.insert()
File "apps/frappe/frappe/model/document.py", line 268, in insert
self.run_post_save_methods()
File "apps/frappe/frappe/model/document.py", line 1010, in run_post_save_methods
self.run_method("on_update")
File "apps/frappe/frappe/model/document.py", line 874, in run_method
out = Document.hook(fn)(self, *args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 1171, in composer
return composed(self, method, *args, **kwargs)
File "apps/frappe/frappe/model/document.py", line 1154, in runner
add_to_return_value(self, fn(self, *args, **kwargs))
File "apps/frappe/frappe/model/document.py", line 868, in
fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
File "apps/frappe_pwa/frappe_pwa/frappe_pwa/doctype/web_app_manifest/web_app_manifest.py", line 16, in on_update
from frappe.website.render import clear_cache
ModuleNotFoundError: No module named 'frappe.website.render'

To Reproduce
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4. See error

Expected behavior
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Screenshots
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Desktop (please complete the following information):

• OS: (e.g. iOS)
• Browser (e.g. chrome, safari)
• Version (e.g. 22)

Smartphone (please complete the following information):

• Device: (e.g. iPhone6)
• OS: (e.g. iOS8.1)
• Browser (e.g. stock browser, safari)
• Version (e.g. 22)

Additional context
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