diff --git a/erpnext/accounts/doctype/dunning/dunning.py b/erpnext/accounts/doctype/dunning/dunning.py
index 719f369..e0d75d3 100644
--- a/erpnext/accounts/doctype/dunning/dunning.py
+++ b/erpnext/accounts/doctype/dunning/dunning.py
@@ -23,7 +23,6 @@
 
 
 class Dunning(AccountsController):
-
 	def validate(self):
 		self.validate_same_currency()
 		self.validate_overdue_payments()
@@ -37,7 +36,11 @@
 		for row in self.overdue_payments:
 			invoice_currency = frappe.get_value("Sales Invoice", row.sales_invoice, "currency")
 			if invoice_currency != self.currency:
-				frappe.throw(_("The currency of invoice {} ({}) is different from the currency of this dunning ({}).").format(row.sales_invoice, invoice_currency, self.currency))
+				frappe.throw(
+					_(
+						"The currency of invoice {} ({}) is different from the currency of this dunning ({})."
+					).format(row.sales_invoice, invoice_currency, self.currency)
+				)
 
 	def validate_overdue_payments(self):
 		daily_interest = self.rate_of_interest / 100 / 365
@@ -55,12 +58,13 @@
 
 	def set_dunning_level(self):
 		for row in self.overdue_payments:
-			past_dunnings = frappe.get_all("Overdue Payment",
+			past_dunnings = frappe.get_all(
+				"Overdue Payment",
 				filters={
 					"payment_schedule": row.payment_schedule,
 					"parent": ("!=", row.parent),
-					"docstatus": 1
-				}
+					"docstatus": 1,
+				},
 			)
 			row.dunning_level = len(past_dunnings) + 1
 
@@ -72,21 +76,26 @@
 	"""
 	for reference in doc.references:
 		if reference.reference_doctype == "Sales Invoice" and reference.outstanding_amount <= 0:
-			unresolved_dunnings = frappe.get_all("Dunning",
+			unresolved_dunnings = frappe.get_all(
+				"Dunning",
 				filters={
 					"sales_invoice": reference.reference_name,
 					"status": ("!=", "Resolved"),
 					"docstatus": ("!=", 2),
 				},
-				pluck="name"
+				pluck="name",
 			)
 
 			for dunning_name in unresolved_dunnings:
 				resolve = True
 				dunning = frappe.get_doc("Dunning", dunning_name)
 				for overdue_payment in dunning.overdue_payments:
-					outstanding_inv = frappe.get_value("Sales Invoice", overdue_payment.sales_invoice, "outstanding_amount")
-					outstanding_ps = frappe.get_value("Payment Schedule", overdue_payment.payment_schedule, "outstanding")
+					outstanding_inv = frappe.get_value(
+						"Sales Invoice", overdue_payment.sales_invoice, "outstanding_amount"
+					)
+					outstanding_ps = frappe.get_value(
+						"Payment Schedule", overdue_payment.payment_schedule, "outstanding"
+					)
 					if outstanding_ps > 0 and outstanding_inv > 0:
 						resolve = False
 
@@ -95,7 +104,6 @@
 					dunning.save()
 
 
-
 @frappe.whitelist()
 def get_dunning_letter_text(dunning_type, doc, language=None):
 	if isinstance(doc, str):
diff --git a/erpnext/accounts/doctype/dunning/test_dunning.py b/erpnext/accounts/doctype/dunning/test_dunning.py
index 6125bd2..be8c533 100644
--- a/erpnext/accounts/doctype/dunning/test_dunning.py
+++ b/erpnext/accounts/doctype/dunning/test_dunning.py
@@ -112,13 +112,16 @@
 
 
 def get_income_account(company):
-	return frappe.get_value("Company", company, "default_income_account") or frappe.get_all(
-		"Account",
-		filters={"is_group": 0, "company": company},
-		or_filters={
-			"report_type": "Profit and Loss",
-			"account_type": ("in", ("Income Account", "Temporary")),
-		},
-		limit=1,
-		pluck="name",
-	)[0]
+	return (
+		frappe.get_value("Company", company, "default_income_account")
+		or frappe.get_all(
+			"Account",
+			filters={"is_group": 0, "company": company},
+			or_filters={
+				"report_type": "Profit and Loss",
+				"account_type": ("in", ("Income Account", "Temporary")),
+			},
+			limit=1,
+			pluck="name",
+		)[0]
+	)
diff --git a/erpnext/accounts/doctype/dunning_type/test_records.json b/erpnext/accounts/doctype/dunning_type/test_records.json
index cb589bf..7f28aab 100644
--- a/erpnext/accounts/doctype/dunning_type/test_records.json
+++ b/erpnext/accounts/doctype/dunning_type/test_records.json
@@ -14,7 +14,7 @@
             }
         ],
         "income_account": "Sales - _TC",
-        "cost_center": "_Test Cost Center"
+        "cost_center": "_Test Cost Center - _TC"
     },
     {
         "doctype": "Dunning Type",
@@ -31,6 +31,6 @@
             }
         ],
         "income_account": "Sales - _TC",
-        "cost_center": "_Test Cost Center"
+        "cost_center": "_Test Cost Center - _TC"
     }
 ]
diff --git a/erpnext/accounts/doctype/payment_entry/payment_entry.py b/erpnext/accounts/doctype/payment_entry/payment_entry.py
index 090308f..2bd703f 100644
--- a/erpnext/accounts/doctype/payment_entry/payment_entry.py
+++ b/erpnext/accounts/doctype/payment_entry/payment_entry.py
@@ -1850,22 +1850,28 @@
 		else:
 			if dt == "Dunning":
 				for overdue_payment in doc.overdue_payments:
-					pe.append("references", {
-						"reference_doctype": "Sales Invoice",
-						"reference_name": overdue_payment.sales_invoice,
-						"payment_term": overdue_payment.payment_term,
-						"due_date": overdue_payment.due_date,
-						"total_amount": overdue_payment.outstanding,
-						"outstanding_amount": overdue_payment.outstanding,
-						"allocated_amount": overdue_payment.outstanding
-					})
+					pe.append(
+						"references",
+						{
+							"reference_doctype": "Sales Invoice",
+							"reference_name": overdue_payment.sales_invoice,
+							"payment_term": overdue_payment.payment_term,
+							"due_date": overdue_payment.due_date,
+							"total_amount": overdue_payment.outstanding,
+							"outstanding_amount": overdue_payment.outstanding,
+							"allocated_amount": overdue_payment.outstanding,
+						},
+					)
 
-				pe.append("deductions", {
-					"account": doc.income_account,
-					"cost_center": doc.cost_center,
-					"amount": -1 * doc.dunning_amount,
-					"description": _("Interest and/or dunning fee")
-				})
+				pe.append(
+					"deductions",
+					{
+						"account": doc.income_account,
+						"cost_center": doc.cost_center,
+						"amount": -1 * doc.dunning_amount,
+						"description": _("Interest and/or dunning fee"),
+					},
+				)
 			else:
 				pe.append(
 					"references",
@@ -1957,8 +1963,10 @@
 
 def set_payment_type(dt, doc):
 	if (
-		dt == "Sales Order" or (dt == "Sales Invoice" and doc.outstanding_amount > 0)
-	) or (dt == "Purchase Invoice" and doc.outstanding_amount < 0) or dt == "Dunning":
+		(dt == "Sales Order" or (dt == "Sales Invoice" and doc.outstanding_amount > 0))
+		or (dt == "Purchase Invoice" and doc.outstanding_amount < 0)
+		or dt == "Dunning"
+	):
 		payment_type = "Receive"
 	else:
 		payment_type = "Pay"
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index b2cd4a6..e3a159b 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -622,7 +622,9 @@
 			return
 
 		if not self.account_for_change_amount:
-			self.account_for_change_amount = frappe.get_cached_value('Company', self.company, 'default_cash_account')
+			self.account_for_change_amount = frappe.get_cached_value(
+				"Company", self.company, "default_cash_account"
+			)
 
 		from erpnext.stock.get_item_details import get_pos_profile, get_pos_profile_item_details
 
@@ -1907,17 +1909,17 @@
 
 @frappe.whitelist()
 def make_maintenance_schedule(source_name, target_doc=None):
-	doclist = get_mapped_doc("Sales Invoice", source_name, {
-		"Sales Invoice": {
-			"doctype": "Maintenance Schedule",
-			"validation": {
-				"docstatus": ["=", 1]
-			}
+	doclist = get_mapped_doc(
+		"Sales Invoice",
+		source_name,
+		{
+			"Sales Invoice": {"doctype": "Maintenance Schedule", "validation": {"docstatus": ["=", 1]}},
+			"Sales Invoice Item": {
+				"doctype": "Maintenance Schedule Item",
+			},
 		},
-		"Sales Invoice Item": {
-			"doctype": "Maintenance Schedule Item",
-		},
-	}, target_doc)
+		target_doc,
+	)
 
 	return doclist
 
@@ -2523,9 +2525,7 @@
 			target.income_account = dunning_type.income_account
 			target.cost_center = dunning_type.cost_center
 			letter_text = get_dunning_letter_text(
-				dunning_type=dunning_type.name,
-				doc=target.as_dict(),
-				language=source.language
+				dunning_type=dunning_type.name, doc=target.as_dict(), language=source.language
 			)
 
 			if letter_text:
@@ -2542,26 +2542,19 @@
 		table_maps={
 			"Sales Invoice": {
 				"doctype": "Dunning",
-				"field_map": {
-					"customer_address": "customer_address",
-					"parent": "sales_invoice"
-				},
+				"field_map": {"customer_address": "customer_address", "parent": "sales_invoice"},
 			},
 			"Payment Schedule": {
 				"doctype": "Overdue Payment",
-				"field_map": {
-					"name": "payment_schedule",
-					"parent": "sales_invoice"
-				},
+				"field_map": {"name": "payment_schedule", "parent": "sales_invoice"},
 				"condition": lambda doc: doc.outstanding > 0 and getdate(doc.due_date) < getdate(),
-			}
+			},
 		},
 		postprocess=postprocess_dunning,
-		ignore_permissions=ignore_permissions
+		ignore_permissions=ignore_permissions,
 	)
 
 
-
 def check_if_return_invoice_linked_with_payment_entry(self):
 	# If a Return invoice is linked with payment entry along with other invoices,
 	# the cancellation of the Return causes allocated amount to be greater than paid
diff --git a/erpnext/patches/v14_0/single_to_multi_dunning.py b/erpnext/patches/v14_0/single_to_multi_dunning.py
index 90966aa..7a8e591 100644
--- a/erpnext/patches/v14_0/single_to_multi_dunning.py
+++ b/erpnext/patches/v14_0/single_to_multi_dunning.py
@@ -18,7 +18,8 @@
 			# something's already here, doesn't need patching
 			continue
 
-		payment_schedules = frappe.get_all("Payment Schedule",
+		payment_schedules = frappe.get_all(
+			"Payment Schedule",
 			filters={"parent": dunning.sales_invoice},
 			fields=[
 				"parent as sales_invoice",
@@ -30,8 +31,8 @@
 				# at the time of creating this dunning, the full amount was outstanding
 				"payment_amount as outstanding",
 				"'0' as paid_amount",
-				"discounted_amount"
-			]
+				"discounted_amount",
+			],
 		)
 
 		dunning.extend("overdue_payments", payment_schedules)