refactor: do not allow submittable doctypes for SLA
diff --git a/erpnext/support/doctype/service_level_agreement/service_level_agreement.js b/erpnext/support/doctype/service_level_agreement/service_level_agreement.js
index bfbffe2..4dbb0e7 100644
--- a/erpnext/support/doctype/service_level_agreement/service_level_agreement.js
+++ b/erpnext/support/doctype/service_level_agreement/service_level_agreement.js
@@ -111,6 +111,7 @@
 				filters: [
 					['DocType', 'issingle', '=', 0],
 					['DocType', 'istable', '=', 0],
+					['DocType', 'is_submittable', '=', 0],
 					['DocType', 'name', 'not in', invalid_doctypes],
 					['DocType', 'module', 'not in', ["Email", "Core", "Custom", "Event Streaming", "Social", "Data Migration", "Geo", "Desk"]]
 				]
diff --git a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
index ea617fd..0334ec8 100644
--- a/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
+++ b/erpnext/support/doctype/service_level_agreement/service_level_agreement.py
@@ -29,6 +29,7 @@
 
 class ServiceLevelAgreement(Document):
 	def validate(self):
+		self.validate_selected_doctype()
 		self.validate_doc()
 		self.validate_status_field()
 		self.check_priorities()
@@ -106,6 +107,23 @@
 			frappe.throw(_("Service Level Agreement for {0} {1} already exists.").format(
 				frappe.bold(self.entity_type), frappe.bold(self.entity)))
 
+	def validate_selected_doctype(self):
+		invalid_doctypes = list(frappe.model.core_doctypes_list)
+		invalid_doctypes.extend(['Cost Center', 'Company'])
+		valid_document_types = frappe.get_all('DocType', {
+			'issingle': 0,
+			'istable': 0,
+			'is_submittable': 0,
+			'name': ['not in', invalid_doctypes],
+			'module': ['not in', ["Email", "Core", "Custom", "Event Streaming", "Social", "Data Migration", "Geo", "Desk"]]
+		}, pluck="name")
+
+		if self.document_type not in valid_document_types:
+			frappe.throw(
+				msg=_("Please select valid document type."),
+				title=_("Invalid Document Type")
+			)
+
 	def validate_status_field(self):
 		meta = frappe.get_meta(self.document_type)
 		if not meta.get_field("status"):