In valuation layer , reference field is related to stock move.

How can i manually pass the value to reference field of valuation 

stock_valuation = self.env['stock.valuation.layer'].create({
    # 'create_date': create_date,
    # 'stock_move_id': stock_move.id or False,
    'product_id': product_id.id or False,
    'company_id': company_id.id or False,
    'quantity': quantity,
    'unit_cost': unit_cost,
    'value': value,
    'description': product_des,

})

stock_valuation.write({'account_move_id': account_move.id,'reference':'Hello' })

reference = fields.Char(related='stock_move_id.reference')