import xmlrpc.client

# Odoo API information: edit it to match your config
url = 'http://localhost:8069'
db = 'MY_DB'
username = 'admin'
password = 'admin'

# Connect to Odoo API
# You may support *sending* None values by passing allow_none=True to the ServerProxy
# In order to *receive* None values you would have to modify odoo core (not recommended)
common = xmlrpc.client.ServerProxy('{}/xmlrpc/2/common'.format(url))
uid = common.authenticate(db, username, password, {})

# Create a connection object
models = xmlrpc.client.ServerProxy('{}/xmlrpc/2/object'.format(url))

# Create and post an invoice
invoice_data = {
    'partner_id': 10,
    'move_type': 'out_invoice',
    'invoice_line_ids': [
        (0, 0, {
            'product_id': 1,
            'quantity': 2,
            'price_unit': 100.0,
        })
    ],
}
invoice_id_1 = models.execute_kw(db, uid, password, 'account.move', 'create', [invoice_data])
invoice_id_2 = models.execute_kw(db, uid, password, 'account.move', 'create', [invoice_data])
invoice_ids = [invoice_id_1, invoice_id_2]
models.execute_kw(db, uid, password, 'account.move', 'action_post', [invoice_ids])

# Prepare values to create send & print wizard
action_vals = models.execute_kw(db, uid, password, 'account.move', 'action_send_and_print', [invoice_ids])

# arguments
# 1) the ORM create() method needs arguments to complete, since that method starts with
# if not vals_list:
#     return self.browse()
# 2) the is_print arg avoids the local printing and downloading of the PDF
# this is simply because account.invoice.send's _print_document() method returns a dict
# containing a None value, which is not supported in xmlrpc unless allow_none is enabled
# 3) the composition_mode is necessary to send multiple e-mails at once
wizard_args = [{'is_print': False, 'composition_mode': 'mass_mail'}]

# keyword arguments: the context contains some necessary values such as active_ids
wizard_kwargs = {'context': action_vals.get('context')}

# Create the wizard
wizard_id = models.execute_kw(db, uid, password, 'account.invoice.send', 'create', wizard_args, wizard_kwargs)

# Use the wizard to send the e-mails
# we provide the context once more as send_and_print_action also relies on it for active_ids
wizard_close = models.execute_kw(db, uid, password, 'account.invoice.send', 'send_and_print_action', [wizard_id], wizard_kwargs)