Update salary dates

I need to change the salary structure for payroll frequency.
The current bimonthly dates were set on 15th and 30th, but i need to have 10th and 25th salary pays.

In the code, I see on: erpnext/hr/doctype/process_payroll/process_payroll.py

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'''

	if payroll_frequency == "Monthly" or payroll_frequency == "Bimonthly" or payroll_frequency == "":
		fiscal_year = get_fiscal_year(start_date, company=company)[0]
		month = "%02d" % getdate(start_date).month
		m = get_month_details(fiscal_year, month)
		if payroll_frequency == "Bimonthly":
			if getdate(start_date).day <= 10:
				start_date = m['month_start_date']
				end_date = m['month_mid_end_date']
				start_date = m['month_mid_start_date']
				end_date = m['month_end_date']
			start_date = m['month_start_date']
			end_date = m['month_end_date']

	if payroll_frequency == "Weekly":
		end_date = add_days(start_date, 6)

	if payroll_frequency == "Fortnightly":
		end_date = add_days(start_date, 13)

	if payroll_frequency == "Daily":
		end_date = start_date

	return frappe._dict({
		'start_date': start_date, 'end_date': end_date

am i in the right file? or is there other way to change it?

Yes, I think you need to change here.