Hi Nikolay Kolesnyk,

I am not sure whether you have added code here because it is not visible.

    As it is One2many field, it cannot be assigned directly; you need to use special commands to create lines in crm.lead.

  Check the below steps:

    1. In crm.lead, define One2many field.

    Logic:

    2. Define an empty list (val_list) -> Loop through sale.order.line and prepare a dictionary of values (dict_value) for each line -> Append it to the list.
val_list = []
for line in sale_rec.order_line:
      val_list.append((0, 0, dict_value))       # (0, 0, {}) is special command that creates a record when executed

    3. Assign val_list to lines while creating and updating crm.lead record.
      {'lines': val_list, ...}

I hope it will be useful to you.

Thanks & Regards,
Email: odoo@aktivsoftware.com
Skype: kalpeshmaheshwari