'Create a message gathering merged leads/opps informations. Using message_post, send a
message explaining which fields has been merged and their new value. `self` is the
resulting merge crm.lead record.
:param opportunities : recordset of merged crm.lead
:returns mail.message posted on resulting crm.lead'

@api.multi
def _merge_notify(self, opportunities):

    self.ensure_one()
    result_type = opportunities._merge_get_result_type()
    merge_message = (_('Merged    leads') if (result_type == 'lead') else _('Merged    opportunities'))
    subject = ((merge_message + ':    ') + ',    '.join(opportunities.mapped('name')))
    message_bodies = opportunities._mail_body(list(CRM_LEAD_FIELDS_TO_MERGE))
    message_body = '\n\n'.join(message_bodies)
    return self.message_post(body=message_body, subject=subject)
