Improve Validation Message in the Payroll Entry (#11937) (#11944)

* change error message from `create_log`

* PEP 8 compliance
diff --git a/erpnext/hr/doctype/payroll_entry/payroll_entry.py b/erpnext/hr/doctype/payroll_entry/payroll_entry.py
index db42339..2f5fae4 100644
--- a/erpnext/hr/doctype/payroll_entry/payroll_entry.py
+++ b/erpnext/hr/doctype/payroll_entry/payroll_entry.py
@@ -10,6 +10,7 @@
 from frappe import _
 from erpnext.accounts.utils import get_fiscal_year
 
+
 class PayrollEntry(Document):
 
 	def on_submit(self):
@@ -23,7 +24,6 @@
 		cond = self.get_filter_condition()
 		cond += self.get_joining_releiving_condition()
 
-
 		condition = ''
 		if self.payroll_frequency:
 			condition = """and payroll_frequency = '%(payroll_frequency)s'"""% {"payroll_frequency": self.payroll_frequency}
@@ -355,6 +355,7 @@
 		self.update(get_start_end_dates(self.payroll_frequency,
 			self.start_date or self.posting_date, self.company))
 
+
 @frappe.whitelist()
 def get_start_end_dates(payroll_frequency, start_date=None, company=None):
 	'''Returns dict of start and end dates for given payroll frequency based on start_date'''
@@ -387,6 +388,7 @@
 		'start_date': start_date, 'end_date': end_date
 	})
 
+
 def get_frequency_kwargs(frequency_name):
 	frequency_dict = {
 		'monthly': {'months': 1},
@@ -396,6 +398,7 @@
 	}
 	return frequency_dict.get(frequency_name)
 
+
 @frappe.whitelist()
 def get_end_date(start_date, frequency):
 	start_date = getdate(start_date)
@@ -410,6 +413,7 @@
 	else:
 		return dict(end_date='')
 
+
 def get_month_details(year, month):
 	ysd = frappe.db.get_value("Fiscal Year", year, "year_start_date")
 	if ysd:
@@ -433,15 +437,21 @@
 	else:
 		frappe.throw(_("Fiscal Year {0} not found").format(year))
 
+
 @frappe.whitelist()
 def create_log(ss_list):
-	if not ss_list or len(ss_list) < 1:
-		frappe.throw(_("No employee for the above selected criteria OR salary slip already created"))
+	if not ss_list:
+		frappe.throw(
+			_("There's no employee for the given criteria. Check that Salary Slips have not already been created."),
+			title='Error'
+		)
 	return ss_list
 
+
 def format_as_links(salary_slip):
 	return ['<a href="#Form/Salary Slip/{0}">{0}</a>'.format(salary_slip)]
 
+
 def create_submit_log(submitted_ss, not_submitted_ss, jv_name):
 
 	if not submitted_ss and not not_submitted_ss: