For v15, assuming you have a Vendor called "ACME Services" and an Expense Account with code "60000" you could do something like:

vendor_name = "ACME Services"
bill_ref = "B65253"
bill_date = "2022-07-01"
bill_date_due = "2022-07-31"
bill_line_note = 'Legal Services'
bill_line_account = '600000'
bill_line_amount = '2500'
bill_line_quantity = 1

vendor_in_odoo = env['res.partner'].search([('name','=',vendor_name)])

if not vendor_in_odoo:
  raise UserError("Cannot find Vendor!")

bill_line_account_in_odoo = env['account.account'].search([('code','=',bill_line_account)])

if not bill_line_account_in_odoo:
  raise UserError("Cannot find Account for the Bill Line!")

bill = env['account.move'].create({
    'move_type': 'in_invoice',
    'invoice_origin': 'External API Demo',
    'partner_id': vendor_in_odoo.id,
    'ref': bill_ref,
    'invoice_date': bill_date,
    'invoice_date_due': bill_date_due,
    'invoice_line_ids': [(0,0,{
      'name': bill_line_note,
      'account_id': bill_line_account_in_odoo.id,    
      'price_unit': bill_line_amount,
      'quantity': bill_line_quantity,
    })],
  })