def load_invoices(file='../data/invoices.json'):
input_file = open(file, encoding='utf-8')
json_array = json.load(input_file)
for inv in json_array:
company = Company.query.get(inv['company_id'])
buyer = Contact.query.get(inv['buyer_id'])
user = User.query.get(inv['user_id'])
issue_date = dt.datetime.strptime(inv['issue_date'], '%Y-%m-%d')
due_date = dt.datetime.strptime(inv['due_date'], '%Y-%m-%d')
invoice = Invoice(issue_date=issue_date,
due_date=due_date,
payment_form=inv['payment_form'],
type=inv['type'],
invoice_buyer=buyer,
invoice_company=company,
invoice_author=user)
invoice.create_serial_number()
db.session.add(invoice)
load_invoice_items(inv['items'], invoice)
invoice.total_sum = sum([item['total_price'] for item in inv['items']])
db.session.commit()
