title: odoo the following fields are invalid
body: <p>In order to consolidate many order lines in one line "quantity, total_price", and try to print it using a button. I got this error <code>the following fields are invalid order_line_consolidation</code>, what I did:</p>
  
  <p>1- created a wizard with a One2many field <code>order_line_consolidation</code></p>
  
  <pre><code>class sale_order_consolidation(models.TransientModel):
  
  _name = "sale.order.consolidation"
  _description = 'consolidation wizard'
  
  order_line_consolidation = fields.One2many('sale.order.line', 'order_id')
  </code></pre>
  
  <p>2- function to consolidate lines, 
  <a href="https://stackoverflow.com/questions/47517038/list-of-dictionary-consolidation">list of dictionary consolidation</a></p>
  
  <p>3- print function</p>
  
  <pre><code>def print_quotation(self, cr, uid, ids, context=None):
  
  
      datas = {}
      if context is None:
  
          context = {} 
      data = self.read(cr, uid, ids)[0]
      datas = {   'ids': [],
                  'model': 'sale.order',
                  'form': data
                  }
  
      return {'type': 'ir.actions.report.xml',
              'report_name': 'sale.report_saleorder',
              'datas': datas
              }
  </code></pre>